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Pennsylvania State University
Astronomy and Astrophysics
University Park, Pennsylvania 16802-6305
This report covers the period from September 1, 2002 to Alex Wolszczan was on sabbatical leave at the California
August 31, 2003. Institute of Technology and Jet Propulsion Laboratory 共Pasa-
dena CA兲, and at the Max-Planck-Institut for Radioas-
tronomy 共Bonn, Germany兲.
1. PERSONNEL
1.3 Visitors to the Department
1.1 Faculty
Visitors to the department included Dr. Shai Kaspi 共from
The regular members of the faculty during the academic Tel Aviv University兲, Dr. Ann Hornschemeier 共Johns Hop-
year 2002-2003 were Professors Peter Mészáros 共Department kins University兲 and Dr. Sarah Gallagher 共Massachusetts In-
Head and Distinguished Professor兲, William Nielsen Brandt, stitute of Technology兲 working with Dr. Niel Brandt; Dr. Ed
Jane Charlton, Robin Ciardullo, Eric Feigelson, Gordon Murphy 共from the University of Virginia兲 working with Dr.
Garmire 共Evan Pugh Professor兲, Pablo Laguna, Lawrence Chris Palma and Dr. Jane Charlton; Dr. John Feldmeier
Ramsey 共Department Head effective July 1兲, Mercedes Rich- 共from Case Western Reserve University兲 working with Dr.
ards, John Nousek, Donald Schneider, Peter Usher 共Emeri- Robin Ciardullo; Prof. Chris Mihos 共from Case Western Re-
tus兲, and Alexander Wolszczan 共Evan Pugh Professor兲; As- serve University兲 and Dr. Kelly Holley-Bockelmann 共from
sociate Professor Richard Wade; Assistant Professors Tom the University of Massachusetts兲 working with Dr. Steinn
Abel, Michael Eracleous, Jian Ge, and Steinn Sigurdsson; Sigurdsson; Mr. Ralf Kaehler 共Zuse Rechenzentrum, Berlin兲,
Senior Scientist/Professor David Burrows; and Senior Scien- Dr. Naoki Yoshida 共Harvard, Center for Astrophysics兲, Dr.
tist George Pavlov. Aaron Sokasian 共Harvard College Observatory兲, Dr. Ken
James Beatty and Lee Samuel Finn, Professors of Physics, Nomoto 共University of Tokyo兲 and Dr. Ari Mahler 共Univer-
and Stephane Coutu and Douglas Cowen, Assistant Profes- sity of Massachusetts, Amherst兲 all working with Dr. Tom
sors of Physics, all hold joint appointments in Astronomy & Abel.
Astrophysics.
Senior Research Associates in the program were George 2. ACADEMIC PROGRAM
Chartas and Leisa Townsley. Research Associates in the pro-
gram were David Alexander, Franz Bauer, Abhijit 2.1 Graduate & Undergraduate Majors
Chakraborty, Margaret Chester, Christopher Churchill, Twenty-five graduate and forty-two undergraduate as-
Patrick Durrell, Audrey Garmire, Konstantin Getman, tronomy majors were enrolled during the academic year
Valdimir Getman, Caryl Gronwall, Joanne Hill, Sally 2002-2003. During that time 13 B.S. degrees and one Ph.D.
Hunsberger, Nina Jansen, Shiho Kobayashi, Koji Mori, degree were awarded in Astronomy & Astrophysics. Doc-
Christopher Palma, Sangwook Park, Soebur Razzaque, De- toral recipient was Michael Sipior.
qing Ren, Peter Roming, Emanuele Ripamonti, Divas San-
wal, Ulrich Sperhake, Marcus Teter, Cristian Vignali and 2.2 Educational Initiatives
Bing Zhang. Joining the department as Research Associates
were Jan Budaj 共formerly of the Slovak Academy of Science, Once again, the Department offered summer graduate
Slovakia兲, Stefan Immler 共formerly of Max-Planck-Institut classes for high-school teachers interested in learning more
für extraterrestrische Physik, Germany兲, Wentao Wu 共for- about astronomy and its potential as a medium for physical
merly of the University of Alabama兲, Toru Misawa 共formerly science education in secondary schools. The 2003 program
of the National Astronomical Observatory, Japan兲, Masahiro entitled, Penn State Inservice Workshops in Astronomy
Tsujimoto 共formerly of Kyoto University, Japan兲 and Alexey 共PSIWA兲, consisted of three 1-week courses: Stars and Plan-
Koptsevitch 共formerly of Ioffe Institute for Physics and ets, Galaxies and Cosmology, and Space Astronomy. All of
Technology, Russia兲. the courses were offered at Penn State’s main campus and
Instructor was Scott Miller. included a variety of classroom, laboratory and computer
Adjunct Associate Professor was Hans Kraus at the Ox- activities. Funding was received from the PA Space Grant
ford University Nuclear and Astrophysics Laboratory. Consortium and NASA. Palma, Feigelson, and Brandt were
the workshop instructors. Numerous department faculty, re-
search associates and graduate students also participated in
1.2 Sabbatical Leaves the programs.
Eric Feigelson was on sabbatical leave at the Centre des
2.3 Outreach
Études de Saclay 共Paris, France兲, Arcetri Observatory 共Flo-
rence, Italy兲, and the University of New South Wales 共Aus- The department outreach effort continued to provide
tralian Defence Force Academy campus, Canberra, Austra- stimulating and educational programs for the general public
lia兲. in 2003. Once again the department hosted the Friedman2 ANNUAL REPORT
Lecture Series, public lectures sponsored by the Ronald and During the last reporting period it was noted that the Me-
Susan Friedman Fund. Dr. Mario Livio of the Space Tele- dium Resolution Spectrograph 共MRS兲, the third HET facility
scope Science Institute presented the first lecture on the ac- instrument for the HET, was installed and had first light. To
celerating universe. Mike Weinstein covered highlights from date the so-called direct feed mode has been commissioned
the Hubble Space Telescope in the second lecture. Once and will be available for queue observing in Dec. 2003. This
again this summer, members from the department teamed up instrument is described in Ramsey et al. 共2003兲.
with volunteer undergraduate students, Astronomy Club During the past year, the following papers were submitted
members, and community members to produce AstroFest: a using HET data: Fan et al. 2003, Mukherjee et al. 2003, Vig-
program featuring numerous astronomical activities held nali et al. 2003, and Lopez-Santiago et al. 2003.
during the Central Pennsylvania Festival of the Arts. More
than 1,100 people visited the department over the four-day
event. Additional public service programs, e.g., planetarium 3.1.2 X-ray
shows, observing with telescopes, and public lectures were 3.1.2.1 Overview of the CCD Imaging Spectrometer on
held throughout the year. A complete listing of outreach pro- Chandra The ACIS instrument on board the Chandra
grams offered by the department may be viewed at: X-ray Observatory continues to return excellent data after
http://www.astro.psu.edu/outreach/outreach.html. four years in orbit. During the past year a number of inter-
esting observations were made by the ACIS team at Penn
2.4 Astronomy Club State ranging from young stars, supernova remnants, neutron
stars, black holes, clusters of galaxies and very distant AGN.
The Astronomy Club continued to conduct monthly pub- During the year members of the ACIS team participated with
lic observing sessions, uninterruptedly since 1973. These the Chandra X-ray Center in discussions of how to remove
Open Houses attract hundreds of visitors to the roof of the material that has been slowly accumulating on the ACIS
Davey Laboratory to view selected celestial objects through filter. A possible bake out of the ACIS camera is being con-
various telescopes. Members also participated in outreach sidered as a means to drive off the contaminant. A. and G.
programs, some of which made use of the department’s plan- Garmire continue to work on the young stellar content of the
etarium. Club officers are: Co-Presidents: Christeallia Amo- cometary dark cloud in Corona Australis and the central
rosi and Brandon Aldinger, Treasurer: Peter Greene, Secre- compact object in the supernova remnant RCW103. Other
tary: Brian Lacki. Eracleous is the Club’s faculty advisor. members of the ACIS team provide descriptions of their
work under their sections.
3. RESEARCH ACTIVITIES 3.1.2.2. Software Development for ACIS Broos has devel-
oped a new software package for the automated extraction
3.1 Instrumentation and fitting of point source spectra from ACIS imaging data,
called acis_extract. It generates lightcurves, photometry, di-
3.1.1 Optical agnostic plots, and other products. Multiple observations of a
3.1.1.1 The Hobby-Eberly Telescope The HET has com- target are handled 共weighted ARFs, RMFs兲. ARFs are low-
pleted its fourth year of early operations. Again this last year ered by the computed PSF fraction 共as a function of energy兲
about 2/3 of HET time was scheduled for science observa- to improve flux estimates. PSF-correlation and data centroid
tions in the queue mode. The remainder of the time was positions are calculated for each source and can be used to
taken up by instrument commissioning and telescope engi- improve source positions. Maximum Likelihood reconstruc-
neering and facility improvements. The facility instruments tion of each source neighborhood allows the user to search
in service this period remain the Low Resolution Spec- for close pairs or groups of sources. Wide-band photometry
trograph 共LRS兲 and the High Resolution Spectrograph is performed and hardness ratios are computed. Automated
共HRS兲. The average shutter open on sky efficiency of the spectral fitting is performed using the composite source spec-
HET during science operations remains about 45%, but the tra, background spectra, RMFs, and ARFs. Getman has de-
program completion rate increased to 80% of the two highest veloped utilities for choosing the best spectral fit and for
rated priority bands. Data were delivered to all five collabo- generating LaTeX tables of photometry and fit parameters.
rating institutions: UT Austin, Penn State University, Stan- He has also provided sample XSPEC model scripts. Broos
ford University, Georg August Universitaet Goettingen, Lud- and Townsley have written an extensive users’ manual. The
wig Maximilians Universitaet Muenchen, and to the US package was released to community in February 2003 共
national community through NOAO. The Pennsylvania State http://www.astro.psu.edu/xray/docs/TARA/ ae_users_guide-
University accounted for roughly 27% of the time. .html兲 and a poster describing it was presented at the March
The HET continues to benefit from engineering and op- 2003 HEAD meeting.
erational upgrades. At the very end of this reporting period Townsley and Broos continue to support their public
the HET achieved its image quality goal during engineering Monte Carlo algorithm to model and predict the response of
delivering 0.88 arc second images in about 0.6 arc second X-ray CCDs to photons and minimally-ionizing particles
seeing 共FWHM兲. All critical problems that relate to delivered 共Townsley et al. 2002a兲. They also continue to support their
image quality have been identified and engineering solutions public code to correct for charge transfer inefficiency 共CTI兲
are in progress. We fully expect to be seeing limited in nor- in ACIS CCDs 共Townsley et al. 2001b兲. The CCD simulator
mal operation in a matter of months. code was used to generate response matrices necessary forPENNSYLVANIA STATE UNIVESITY 3
ACIS spectral fitting of CTI-corrected data. The simulator protoplanetary disks can often be long-lived. The census of
and CTI corrector code are available to the entire X-ray as- Cha members is now nearly complete. The higher mass
tronomy community 共http://www.astro.psu.edu/users/ members clearly congregate in the cluster core; this mass
townsley/cti/兲; a similar CTI corrector has been implemented segregation must be innate to the star forming process is
共for frontside-illuminated CCDs only兲 by the Chandra Sci- present. Feigelson also lead a Chandra study of the immedi-
ence Center in their CIAO software package. ate vicinity of the 3⫺5 Myr-old stars ⑀ Cha and HD 104237.
The latter, a well-known intermediate-mass Herbig AeBe
3.1.3 Multiple Wavelength Missions
star, is found to have at least 4 stellar companions within
3.1.3.1 The Swift Gamma Ray Burst Explorer Penn State 1500 AU. This is the highest multiplicity pre-main sequence
supplied instruments 共the X-Ray Telescope and UV-Optical system known, and requires a quiescent dynamical environ-
Telescope兲 have been successfully integrated and tested ment to have survived.
aboard the Swift Gamma-ray Burst Explorer satellite. The Feigelson served as a collaborator in several other Chan-
Swift Mission Operations Center has completed develop- dra studies of X-ray emission and magnetic activity in young
ment and is ready to begin its State College-based operations stars. These include elucidation of X-rays from the base of
control when Swift is launched 共projected May 2004兲. Swift the Herbig-Haro outflow from a protostar 共J. Bally, lead兲,
is expected to discover, accurately position and retrieve data description of a remarkably powerful and slow X-ray flare in
from optical, X-ray and gamma-ray emission of bursts and a weak-lined T Tauri star 共N. Grosso, lead兲, discovery of
afterglows in unprecedented numbers. Working with the X-rays from an older pre-main sequence brown dwarf 共Y.
Goddard Space Flight Center team, the Penn State Mission Tsuboi, lead兲, and a new determination of the interstellar
Operations Center will be the focus of world-wide attention gas-to-dust ratio from X-ray absorption of embedded young
in a new era of burst science. stars 共M. Vuong, lead兲. Feigelson presented various stellar
Chandra results at workshops Magnetism and activity of the
3.2 Observational Research Sun and Stars 共Toulouse FR兲 and Mineralogie du systeme
solaire 共Lille FR兲, at the IAU Symposium 219 Stars as Suns
3.2.1 Planetary & Stellar Astronomy 共Sydney AU兲, and in talks at a number of institutions in
3.2.1.1 Planetary Systems Konacki 共Caltech兲 and Wolszc- Europe and Australia.
zan 共PSU兲 have measured masses and orbital inclinations of Townsley, Feigelson, Broos, Garmire, and colleagues
the two terrestrial-mass planets around the pulsar PSR completed a large paper on diffuse X-ray emission in the
B1257⫹12. The planets are about 4 times the mass of the high-mass star-forming regions M 17 and the Rosette Nebula
Earth and their orbits are approximately coplanar suggesting 共Townsley et al. 2003; also see the Chandra Science Center
a disk origin of the system. This result is the first precise image release on M 17, http://chandra.harvard.edu/photo/
mass measurement for low-mass planets beyond the solar 2003/m17/, and the press release on the Rosette Nebula,
system. http://chandra.harvard.edu/photo/cycle1/2237/兲. The Chandra
3.2.1.2 Star Formation Feigelson continued his Chandra observation of M 17 described here complements the
imaging studies of the rich young stellar cluster in the Orion ROSAT observation of this field 共Dunne et al. 2003兲, show-
Nebula. The principal result published this year is that the ing that soft diffuse X-ray emission fills this blister H II
magnetic activity of pre-main sequence stars, using X-ray region and may be flowing through its blown-out edge into
luminosity as the activity tracer, does not depend on stellar the ISM. This hot plasma is probably generated by the winds
rotation as it does in main sequence stars. Instead, activity is from the OB cluster powering the H II region. The discovery
broadly linked to a combination of stellar mass, bolometric of this diffuse plasma, after 30 years of theoretical work
luminosity, and surface area. These relationships have not showing that it should exist, was only possible because of the
been predicted and are not understood. One possibility is that high spatial resolution of the Chandra X-ray Observatory;
magnetic fields in the pre-main sequence phase are not gen- this allowed us to resolve the diffuse plasma from the ⬎900
erated by the rotation-dependent differential rotation of the stellar sources in the cluster.
␣ ⫺⍀ dynamo operating in main sequence stars, but rather Townsley, Feigelson, Broos, Garmire, Getman, and col-
by a turbulent dynamo distributed throughout the deep con- leagues obtained the first high-spatial-resolution X-ray im-
vection zone. ages and spectra of RCW 49, a bright southern H II region
Feigelson now leads an international consortium that is powered by the dense stellar cluster Westerlund 2, in a 36-
expanding the X-ray study of the Orion Nebula. The Chan- ksec observation with the Advanced CCD Imaging Spec-
dra Orion Ultradeep Project 共COUP兲 subjected the region for trometer 共ACIS兲 aboard the Chandra X-ray Observatory in
10 days of nearly continuous exposure, giving unprecedented August 2003. This rich high-mass star-forming region re-
long and high-signal light curves of more than 1600 magneti- veals a complex mix of point source and diffuse X-ray emis-
cally active stars. Data analysis is underway and science re- sion. The cluster is resolved at the arcsecond level into hun-
sults should emerge in 2004-05. dreds of sources. Diffuse X-ray emission with at least three
Feigelson works with Lawson and graduate student Lyo thermal plasma components 共0.1, 0.8, and ⬎3 keV兲 pervades
共UNSW@ADFA兲 in the study of sparse clusters of X-ray the H II region and is resolved from the point source popu-
discovered older T Tauri stars. JHKL observations of the lation. This extended emission is most likely from the fast
ROSAT-discovered 9 Myr-old Cha cluster showed that O-star winds that thermalize and shock the surrounding me-
2/3 of these stars show an L-band excess, indicating that dia; similar plasmas have been seen in other high-mass star-4 ANNUAL REPORT
forming regions, but RCW 49 is the first region to show all near-IR J, H, and K s magnitudes for more than 800 hot sub-
three components. As such, it serves as a very useful dwarfs 共sdO and sdB stars兲 drawn from the ‘‘Catalogue of
‘‘bridge’’ target, linking their observations of nearby regions Spectroscopically Identified Hot Subdwarfs’’ of Kilkenny
such as M 17 and Rosette with other studies of more distant, et al. This sample size greatly exceeds that of previous stud-
massive complexes such as NGC 3603, W 51, and the ies of hot subdwarfs. From 2MASS photometry alone or in
Arches Cluster. combination with visual photometry 共Johnson BV or
3.2.1.3 Cataclysmic Variables An extensive grid of syn- Strömgren u v by) available in the literature, it is possible to
thetic mid- and far-ultraviolet spectra for accretion disks in identify hot subdwarf stars that exhibit atypically red IR col-
cataclysmic variables has been presented by Wade & ors, which can be attributed to the presence of an unresolved
Hubeny. In those models, the disk was assumed to be in late-type companion. Using this large sample, it was possible
steady state; that is, T eff(r) is specified completely by the to define for the first time an approximately volume-limited
sample of hot subdwarfs. The considerations, biases, and dif-
mass M WD and radius R WD of the accreting white dwarf star
ficulties in defining such a sample were discussed. They find
and the mass transfer rate Ṁ , which is constant throughout
that, of the hot subdwarfs in Kilkenny et al., about 40% in a
the disk. In those models, T eff(r)⬀r ⫺3/4, except as modified magnitude-limited sample have colors that are consistent
by a cutoff term near the white dwarf. Actual disks may vary with the presence of an unresolved late-type companion. Bi-
from the steady state prescription for T eff(r), however, as a nary stars are over-represented in a magnitude-limited
result of, for example, outburst cycles in dwarf novae (Ṁ not sample. In an approximately volume-limited sample the frac-
constant with radius兲 or irradiation 共in which case T eff in the tion of composite-color binaries is about 25%.
outer disk is raised above T steady). To show how the spectra Wade and Stark considered whether the hypothesis that
of such disks might differ from the steady case, J. A. Orosz ‘‘all 共or most兲 hot subdwarf stars are in close binaries’’ is
共San Diego State Univ.兲 and Wade carried out a study of the supported by the frequently reported observations of photo-
ultraviolet spectra of models in which power-law tempera- metrically or spectroscopically composite character of many
ture profiles T eff(r)⬀r ⫺ ␥ with ␥ ⬍3/4 are specified. Other- hot subdwarfs. As a possible counter-argument, they drew
wise, the construction of the models is the same as in the attention to resolved companions 共optical pairs兲 of hot sub-
Wade & Hubeny grid, to allow comparison. Both the UV dwarf stars. On a statistical basis, many of these are physi-
spectral energy distributions and the appearance of the UV cally associated with the hot subdwarfs, i.e., are common
line spectra were considered, and a brief discussion of the the proper motion pairs. These resolved pairs make a several
eclipse light curves of the nonstandard models was given. percent contribution to the catalog of hot subdwarf stars per
Comparison of these models with UV observations of nova- decade in projected separation. If they are just the relatively
like variables suggests that better agreement may be possible wide members of a binary population similar to the local
with such modified T eff(r) profiles. G-dwarf binary population, which has a very wide distribu-
AM CVn is an ultra-short-period Helium cataclysmic tion of orbital separations, then many of the unresolved but
variable. An interesting question is whether the accretion composite hot subdwarf binaries may not be ‘‘close’’ in the
disk or the accreting white dwarf dominates the UV spec- astrophysical sense. In that case, binary channels for hot sub-
trum from this object. Wade and Eracleous obtained HST/ dwarf formation may be less important than thought, or must
STIS observations of the UV spectrum of AM CVn on 2002 involve companions 共white dwarfs兲 that do not result in a
Feb 21, using the NUV MAMA with grating G230L to ob- composite spectrum system.
tain 1925 s of time-tagged data covering 1600-3150 Å, and
3.2.1.5 Chemically Peculiar Stars Budaj wrote a review
using the FUV MAMA with grating G140L to obtain 2400 s
paper on Chemically Peculiar Stars for Kozmos, a popular
of time-tagged data covering 1140-1710 Å. Thus, complete
Slovak astronomical journal 共in Slovak兲.
orbital coverage of the binary star was obtained, but not cov-
Budaj and Jozef Drga 共graduate student; Faculty of Math-
erage of the 13.4 h precessional period of the eccentric disk.
ematics, Physics and Informatics of the Commenius Univer-
The mean spectrum is approximately flat in f . The absorp-
sity, Bratislava, Slovakia兲 are studying the evolutionary sta-
tion profiles of the resonance lines of N V, Si IV, C IV, and
tus of Ap binaries by constructing the HR diagram of a
N IV are blue-shifted, evidencing a wind that is partly oc-
sample Ap and comparison normal binaries. Ap binaries
culted by the accretion disk. There is weak emission at NV,
seem to be slightly older than the normal binaries but do not
which also shows the deepest absorption. The He II 1640 Å
differ from the single Ap star in this respect.
line is asymmetric. Numerous weaker spectral features of Budaj and Marian Fenovcik 共graduate student; University
various widths are found. Sharp 共interstellar兲 absorption lines of Pavol Jozef Safarik, Kosice, Slovakia兲 are working on the
are also seen. The light curve shows both short–term fluc- calculation of synthetic spectra and the subsequent abun-
tuations and a long-term decline by about 15% over the span dance analysis of six Am binaries.
of the observations. The UV energy distribution will be com- Budaj and Ilian Iliev 共National Astronomical Observa-
bined with data from other wavelengths to study the contri- tory, Bulgaria兲 suggested that the tidally induced meridional
bution of the stellar components and the accretion disk in circulation of Tassoul & Tassoul might successfully compete
this system. with the diffusion processes and rotationally induced meridi-
3.2.1.4 Hot Subdwarf Stars Stark and Wade, along with G. onal circulation in chemically peculiar stars. They have be-
B. Berriman 共IPAC兲, used the Two Micron All Sky Survey gun a systematic abundance analysis of a sample of Am bi-
共2MASS兲 All-Sky Data Release Catalog to retrieve useful naries to search for possible observable abundance anomaliesPENNSYLVANIA STATE UNIVESITY 5
driven by tidal interaction in these systems. The first three Nousek have acquired spatially-resolved spectral analysis of
stars, HD 33254, HD 178449, HD 198391 have already been a Galactic oxygen-rich SNR G292.0⫹1.8 which has revealed
analyzed. the detailed explosive nucleosynthesis products and sites
Budaj with collaborators from Bulgaria and Slovakia from the massive progenitor star 共Park et al. 2003c兲. Their
共Iliev, Barzova, Ziznovsky, Zverko, Stateva兲 determined the Chandra/ACIS observation of G292.0⫹1.8 has resolved the
mass ratio of two double-lined spectroscopic binary 共SB2兲 SN ejecta material and the asymmetric CSM down to
Systems: HD 108642 and HD 434. ⬃arcsec angular scale. Their spectral analysis of these ejecta
3.2.1.6 Multiwavelength and Multi-epoch Observations Ri- knots over the SNR suggested that the ejecta material in this
chards has collected new time domain observations of Algol SNR is dominated by low-Z elemental species of oxygen,
binaries with the Hobby-Eberly Telescope high resolution neon, and magnesium which have originated from the outer
spectrograph during the Fall 2002 and Spring 2003 semes- layers of the ‘‘unprocessed’’ 共i.e., the hydrostatic He-
ters. She obtained 16 spectra of S Equ within two months burning兲 carbon-core. They found no evidence for the nu-
and 25 spectra of AU Mon within 6 weeks. These spectra cleosynthesis products of the explosive Ne-, O- or Si-burning
will be used to produce new multiwavelength Doppler im- process from the deep interior of the progenitor. This is con-
ages of these systems at wavelengths from 4800 Å to 6700 trast to the case for another Galactic O-rich SNR Cassiopeia
Å. A, where ejecta material dominated by high-Z elements 共Si,
Richards, Budaj, and Ilian Iliev 共National Astronomical S, and Fe兲 was found. The absence of high-Z elements indi-
Observatory, Bulgaria兲 have begun a campaign to collect cates that, unlike Cas A, the turn-over of the ejecta material
spectra of several active Algols like U CrB, and U Sge over was not effective in G292.0⫹1.8 and that the reverse shock
repeated epochs. This campaign that will provide spectra that has not reached the heavy elements near the center of the
can be used to make multi-epoch Doppler tomograms of the SNR. They also found a significant pressure difference be-
H␣ and He I gas flows over a 3- or 4-month period. The tween the CSM and the pulsar wind nebula 共PWN兲 from the
campaign began in September 2003 and is in progress. associated pulsar. This non-equilibrium pressure strongly
supports their interpretation for the non-detection of heavy
3.2.1.7 Doppler Tomography Richards was Chair of the Sci-
elements in terms of the unshocked heavy element ejecta in
entific Organizing Committee for IAU Joint Discussion No.
the center of the SNR.
9 on ‘‘Astrotomography,’’ that was held at the IAU General
Chandra/ACIS observations of SNRs in the Magellanic
Assembly XXV, in Sydney, Australia, July 17 - 21, 2003.
Clouds by Park, Burrows, Garmire, and Nousek have re-
Richards and Milind Cholkar 共graduate student兲 have
vealed the presence of magnesium- and oxygen-rich ejecta in
been studying various techniques to invert Doppler tomo-
SNRs N49B and 0103⫺72.6, respectively 共Park et al.
grams of Algol binaries to produce Cartesian images of the
2003d,e兲. These SNRs are relatively old ( ⬃104 yr兲 and thus
multiple accretions structures identified in these systems.
the detection of metal-rich ejecta from these objects is re-
3.2.1.8 Radio Flares from RS CVn and Algol Binaries Rich- markable. SNR 0103⫺72.6 marks only the second member
ards and Michael Rogers 共undergraduate student兲 are study- of the class of O-rich SNRs in the Small Magellanic Cloud
ing the right and left circular polarized radio flare data from 共SMC兲 and the oldest example ( ⬃18000 yr兲 of all known
several binary systems. They are using the 2.3 GHz 共S band兲 O-rich SNRs. The Mg-rich ejecta material discovered in
and 8.3 GHz 共X band兲 radio flare data collected with the N49B apparently is not accompanied by O- and Ne-rich ma-
NRAO–Green Bank Interferometer nearly continuously over terial. This is mysterious because standard SN nucleosynthe-
2096 days 共5.7 years兲. Flares on two RS CVn binaries 共V711 sis models predict a significant production of O and Ne ma-
Tau and UX Ari兲 and two Algol-type binaries (  Per and ␦ terial together with Mg. With the Chandra/ACIS observation
Lib兲 are being analyzed. This study will focus on the statis- of a Large Magellanic Cloud 共LMC兲 SNR N49, they have
tical properties of the circular polarized data. also discovered a ‘‘bullet’’ of the ejecta material expelled
3.2.1.9 Supernova Remnants Park, Burrows, and Garmire from the progenitor star 共Park et al. 2003f兲. The blast wave
have been monitoring SNR 1987A with the Chandra/ACIS, shock from N49 is interacting with dense, clumpy molecular
twice a year separated roughly by 6 months. As of July 2003 clouds, and they found good evidence for multiple-phase
they have performed a total of eight Chandra/ACIS observa- shock structure, with three characteristic electron tempera-
tions of SNR 1987A. The latest results include the detection tures, due to the shock-cloud interaction. They also unam-
of emergence of new X-ray bright spots in both eastern and biguously detect the associated point-like source which is
the western side of the SNR, non-linearly brightening of the most likely the X-ray counterpart of the soft ␥ -ray repeater
soft X-ray flux, radial expansion of the SNR with a blast 共SGR兲 0526⫺66 in a quiescent phase. They confirm a very
wave shock velocity of ⬃5000 km s⫺1 , and spectral soften- soft power law spectrum from this SGR. Mori, Burrows,
ing due to the interaction between the blast wave and the Hester 共Arizona State兲 and collaborators have performed
dense circumstellar medium 共CSM兲 共Park et al. 2003a,b兲. monitoring observations of the Crab Nebula with the Chan-
The X-ray ring of SNR 1987A is now nearly complete, and dra X-ray observatory and Hubble space telescope for five
they expect a dramatic brightening of the SNR as the blast months. The Crab nebula is the prototypical pulsar wind
wave is sweeping through the main body of the dense inner nebula 共PWN兲, which is powered by the spin-down energy
ring. Their monitoring observations in coming years should of the pulsar. It has long been known that the inner region of
be able to detect this exciting event of the ‘‘birth’’ of a the Crab Nebula is dynamically variable, but the origin of the
supernova remnant. sloppypar Park, Burrows, Garmire and variation was unresolved mainly due to the lack of spatial6 ANNUAL REPORT
and temporal resolution. The monitoring observations using wind nebula 共PWN兲, Pavlov, Teter, Kargaltsev, and Sanwal
two great observatories for the first time identified the origin discovered a dim, curved outer jet that extends up to ⬃100⬙
of the variations with the variable inner ring and wisps along the direction of the pulsar’s proper motion. The jet
emerging from it. This work observationally confirmed that shows strong variability, changing its shape and brightness.
these dynamical features were associated with the termina- Bright blobs move along the jet with apparent speeds (0.3
tion shock of the pulsar wind and its downstream flow, ⫺0.6)c and fade on timescales of days to weeks. The spec-
which were only theoretically discussed so far. trum of the outer jet fits a power-law model with a photon
Mori, Burrows, Pavlov, and collaborators have newly dis- index ⌫⫽1.3⫾0.1. The apparent average luminosity of the
covered long-term 共years兲 morphological variations of the outer jet in the 1-8 keV band is 3⫻1030 ergs s⫺1 , compared
Crab Nebula in addition to previously known short-term to 6⫻1032 from the whole PWN. The X-ray emission of the
共days to months兲 variations. The long-term variations are outer jet can be interpreted as synchrotron radiation of ul-
clearly recognized at the torus and the southern jet. The dis- trarelativistic electrons/positrons. This interpretation allows
placements of these variations are as large as a few arcsec- one to estimate the magnetic field, ⬃100 G, maximum
onds so that only Chandra, with its superb spatial resolution, energy of X-ray-emitting electrons, ⬃2⫻1014 eV, and en-
can resolve them. Through Chandra observations over 3 ergy injection rate, ⬃8⫻1033 ergs s⫺1 . In the summed PWN
years, the torus appears to have been expanding until the image, a faint, strongly bent, extension of the outer jet is
midpoint of this period, but to have shrunk in the latest ob- seen. This bending could be caused by combined action of a
servation. Considering the fact that the angular extent of the wind within the supernova remnant, with a velocity of a few
torus 共radius ⬃ 50 ⬙ 兲 is almost constant over 25 years, the ⫻10 km s⫺1 , along with the ram pressure due to the pulsar’s
torus may repeat expansions and contractions with an ampli- proper motion. The more extreme bends closer to the pulsar,
tude of a few arcseconds and a time scale of about a decade. as well as the apparent side motions of the outer jet, can be
The southern jet shows the growth of its overall kinked associated with kink instabilities of a magnetically confined,
structure. The similarity of the jet variability to that of Vela, pinched jet flow. Another feature found in the summed im-
another famous variable PWN, suggests that a common age is a dim, ⬃2 ⬘ long outer counterjet, which also shows a
mechanism like MHD instability is responsible for the vari- power-law spectrum with ⌫⯝1.2–1.5. Southwest of the jet/
ability of the Crab and Vela jet. counterjet 共i.e., approximately perpendicular to the direction
Mori, Tsunemi 共Osaka兲, Burrows, Garmire, and collabo- of pulsar’s proper motion兲, an extended region of diffuse
rators have observed Titan’s transit of the Crab Nebula on 5 emission is seen. Relativistic particles responsible for this
January 2003 with Chandra. Titan is Saturn’s largest satellite radiation are apparently supplied by the outer jet.
and the only satellite in the solar system with a thick atmo- Mignani 共ESO兲, De Luca 共Milan兲, Kargaltsev, Pavlov,
sphere, whose pressure near the surface is about 1.5 times Zaggia 共Trieste兲 Caraveo 共Milan兲, and Becker 共MPE兲 ana-
greater than that of the Earth at sea level. Although the Sat- lyzed deep optical images of the Vela pulsar wind nebula
urnian system has a conjunction with the Crab Nebula every 共PWN兲 observed with HST, NTT and VLT, in various bands,
30 years, it transits the Crab Nebula only about once in sev- and compared the optical images with those obtained with
eral hundred years because of an average offset of a few the Chandra ACIS. Although some features are seen in the
degrees, making its occurrence in 2003 a ‘‘once-in-a- optical images, no correlation with the X-ray structure was
lifetime’’ event. An ‘‘occultation shadow’’, which was made found. Therefore, the diffuse optical emission is more likely
by Titan blocking the X-rays from the Crab Nebula, has associated with filaments in the host Vela supernova rem-
clearly been detected and is found to be larger than the di- nant. The derived upper limits on the optical flux from the
ameter of Titan’s solid surface. The difference gives a thick- PWN are compatible with the values expected on the basis of
ness for Titan’s atmosphere of 882 ⫾ 64 km. This value is the extrapolations of the X-ray data.
slightly larger than those estimated from earlier Voyager ob- Becker 共MPE兲, Swartz 共MSFC兲, and Pavlov, with their
servations, suggesting the possibility of temporal variation in co-authors from MSFC, MIT, and ESO, observed the globu-
the atmospheric thickness. lar cluster M28 with the Chandra X-ray Observatory. They
3.2.10 Neutron Stars and Pulsars Mignani 共ESO兲, Manches- showed that the apparently extended X-ray core emission
ter 共ATNF兲, and Pavlov presented the results of deep optical seen with the ROSAT HRI is due to the superposition of
observations of the old 共100 Myr兲, nearby, isolated pulsar multiple discrete sources, for which the X-ray luminosity
J0108-1431 with the ESO Very Large Telescope. Observa- function is determined down to a limit of about 6⫻1030 ergs
tions with the Australia Telescope Compact Array were s⫺1 . The phase-averaged X-ray spectrum of the 3.05 ms pul-
made to determine an accurate position for the radio pulsar at sar B1821–24 is best described by a power law with photon
the current epoch. The imaging data reveal no counterpart at index ⌫⯝1.2. Marginal evidence of an emission line cen-
the revised radio position down to V⫽28, B⫽28.6, and tered at 3.3 keV in the pulsar spectrum is found, which could
U⫽26.4. For a distance of 130 pc, estimated from the pul- be interpreted as cyclotron emission from a corona above the
sar’s dispersion measure, the constraints on the optical flux pulsar’s polar cap if the magnetic field is strongly different
put an upper limit of T⫽4.5⫻104 K for the surface tempera- from a centered dipole. Spectral analyses of the five brightest
ture of the neutron star, assuming a stellar radius R⫽13 km. unidentified sources is presented. The brightest of these
An upper limit on the pulsar proper motion of 82 mas yr⫺1 sources is interpreted as a transiently accreting neutron star
implies a transverse velocity of ⬍50 km s⫺1 . in a low-mass X-ray binary, in quiescence. Fitting its spec-
From a series of deep observations of the Vela pulsar trum with a hydrogen neutron star atmosphere model yieldsPENNSYLVANIA STATE UNIVESITY 7
⫹30
the effective temperature T eff⫽90⫺10 eV and the radius Their best-fit solution suggests that the M33’s vertical veloc-
⫹6.9
R NS⫽14.5⫺3.8 km. ity dispersion decreases exponentially with a scale length
Rutledge 共CalTech兲, Bildsten 共UCSB兲, Brown 共Univ. Chi- that is more than two times larger than the scale length of the
cago兲, Pavlov, and Zavlin 共MPE兲 observed the type I X-ray- galaxy’s infrared K-band luminosity. Coupled with the iso-
bursting low-mass X-ray binary KS 1731–260 in quiescence, thermal disk approximation, these observations imply that
following a 13 yr long outburst which ended in 2001 Febru- the V-band mass-to-light ratio of M33’s disk ranges from
ary. They show that the emission area radius for a H atmo- M /L V ⬃0.5 in the galaxy’s inner regions to M /L V ⬃2.4 at
sphere spectrum is consistent with that observed from other ⬃10 kpc. The data also show that the ‘‘maximal disk’’ as-
⫹30
quiescent neutron star transients, R⫽23⫺15 (d/8 kpc) km. sumption for spiral galaxy rotation curves is reasonable, at
Unlike all other known transient neutron stars, the duration least in the inner regions of galaxies. sloppypar
of this recent 共and the only observed兲 outburst is as long as 3.2.2.3 Intracluster Stellar Populations Ciardullo, Feldmeier
the thermal diffusion time of the crust. The large amount of 共CWRU兲, Jacoby 共WIYN兲, and Durrell have continued their
heat deposited by reactions in the crust will have heated the large scale surveys for planetary nebulae and red giant stars
crust to temperatures much higher than the equilibrium core in the intergalactic space of nearby groups and clusters. To
temperature. As a result, the thermal luminosity currently date, their 关O III兴 5007 surveys for planetary nebulae cover
observed from the neutron star is dominated not by the core 0.97 deg2 in Virgo, 0.56 deg2 in Fornax, 1.08 deg2 in the
but by the crust. Simulations of the evolution of the quies- M81 Group, and 0.13 deg2 in a blank control field. in Virgo
cent light curve for different scenarios of the crust micro- and the M81 Group, their complementary red giant star sur-
physics demonstrate that monitoring observations 共with cur- veys cover 10.7 arcmin2 and 0.3 deg2 , respectively. The data
rently flying instruments兲 spanning from 1 to 30 yr can from these surveys suggest that intracluster stars are moder-
measure the crust cooling timescale and the total amount of ately old (2 Gyr⬍ ⬍12 Gyr兲, moderately metal-rich
heat stored in the crust. This makes KS 1731-260 a unique (⫺0.8⬍ 关 Fe/H 兴 ⬍⫺0.2), not centrally condensed, and not
laboratory for studying the thermal properties of the crust by
dynamically relaxed. The data also show that intracluster
monitoring the luminosity over the next few years to de-
stars in the M81 Group are rare 共only a couple percent of the
cades.
stars are intracluster兲, but in systems such as Fornax and
Virgo, these objects comprise between 10% and 20% of the
3.2.2 Extragalactic Astronomy cluster.
Durrell, DeCesar 共PSU undergraduate兲, Ciardullo,
3.2.2.1 Extragalactic Planetary Nebulae Ciardullo, Durrell,
Hurley-Keller 共CWRU兲, and Feldmeier 共CWRU兲 have un-
Laychak 共PSU undergraduate兲, Herrmann, Moody 共PSU
dertaken a deep wide-field VI survey of the M81 group of
graduate students兲, Jacoby 共WIYN兲, and Feldmeier 共CWRU兲
galaxies 共using the CFH12K camera on the Canada-France-
have completed an 关O III兴 5007 photometric survey of the
Hawaii Telescope兲 in order to search for stars that may lie
planetary nebulae 共PNe兲 of M33. By using a sample of 152
between the primary galaxies. Preliminary results from the 2
PNe, they demonstrated that the bright end of the the gal-
science fields show that there are few RGB stars in a field
axy’s 关O III兴 5007 planetary nebula luminosity function
located 50-80 kpc from M81; the intragroup fraction is
共PNLF兲 has the same sharp cutoff seen in other galaxies.
small, comprising ⬍2% of the total galactic luminosity. In
From the apparent magnitude of this cutoff, they derive a
⫹0.07 addition to the red stars, clumps of blue stars have also been
galactic distance modulus of (m⫺M ) 0 ⫽24.86⫺0.11 , for a
⫹0.03 discovered within the HI tidal arm between M81 and NGC
distance of 0.94⫺0.05 Mpc. Although this value is ⬃0.3 mag
3077. Color-magnitude diagrams of two of these clumps
larger than the Cepheid distance, the discrepancy likely
show that these blue stars have formed as recently as 30-70
arises from differing assumptions about the system’s internal
Myr, or long after the most recent interactions that formed
extinction. Their photometry also reveals that the faint-end
the HI streamers. Both objects are ⬃1 kpc across and con-
of M33’s PN luminosity function is non-monotonic, with an
sidered tidal dwarf candidates.
inflection point ⬃2 mag below the PNLF’s bright limit. This
feature is probably due to the galaxy’s large population of 3.2.2.4 Stellar Populations Durrell, Harris 共McMaster兲 and
high core-mass planetaries. Pritchet 共U. Victoria兲 have nearly completed their VI survey
of the RGB stars in the outer halo of M31 using the 8K
3.2.2.2 Galaxy Kinematics Ciardullo, Durrell, Laychak, Her-
mosaic camera at the Canada-France-Hawaii Telescope. The
rmann, Moody, Jacoby 共WIYN兲, and Feldmeier 共CWRU兲
have completed a radial velocity survey of 140 PNe in the I, (V⫺I) color-magnitude diagram of a halo field located 30
disk of M33. They have, for the first time, measured the kpc from the M31 nucleus shows that the halo population in
velocity ellipsoid of a galactic disk throughout the body of a this distant field has a metallicity distribution function
galaxy. They show that M33’s line-of-sight velocity disper- 共MDF兲 similar in form 共a dominant metal-rich population兲 to
sion varies little over ⬃4 optical disk scale lengths, and that found in a field located at 20 kpc. Durrell and Côté
demonstrate that this apparent constancy is due to a combi- 共Rutgers兲 are currently working on a Keck photometric VI
nation of factors, including a decline in the disk’s radial ve- study of 3 fields in the outer halo of M31 to investigate the
locity dispersion at galactocentric radii less than ⬃4 kpc, MDF of the red-giant stars in these regions.
and a gradient in the ratio of the vertical to radial velocity 3.2.2.5 Dwarf Galaxies Palma, Hunsberger, Charlton, Dur-
dispersion. They then use their data to derive the dynamical rell, and Gallagher 共now at UCLA兲 have cataloged the can-
scale length of M33’s disk, and the disk’s mass-to-light ratio. didate dwarf galaxies in Hickson Compact Group 92,8 ANNUAL REPORT
Stephan’s Quintet, using their it Hubble Space Telescope ability of the energies and widths of the X-ray BALs in PG
images of the group. Among this sample, they find that sev- 1115⫹080 and APM 08279⫹5255 over timescales of 19 and
eral of the bluest star forming regions are aligned with an 1.8 weeks 共proper-time兲, respectively. The BAL variability
Hsc I tidal tail that has no optical counterpart. Depending on in APM 08279⫹5255 supports their earlier conclusion that
the fate and nature of these objects, a tidal origin of dwarf these absorbers are most likely launched at relatively small
galaxies may be more common than if only optical tails were radii of ⱗ ⬍1016(M BH /M 8 ) 1/2 cm.
responsible. Chartas in collaboration with Dai, Eracleous, and Garmire
Knierman 共a PSU undergraduate student now at Arizona兲, reported results from a mini-survey of relatively high red-
Charlton, Hunsberger, Gallagher, and collaborators pub- shift 共1.7 ⬍z⬍ 4兲 gravitationally lensed radio-quiet quasars
lished results on the formation of star clusters in tidal debris. observed with the Chandra X-ray Observatory. The magni-
They searched HST/WFPC2 images of four colliding galaxy fication effect allows a search for changes in quasar proper-
pairs and found many blue clusters in the western tail of ties such as the accretion process over three orders of mag-
NGC 3256, and varying numbers in other regions. They in- nitude in intrinsic X-ray luminosity, a search for evolution of
dicated that it is not obvious what factors 共e.g. H I mass, X-ray variability, and extends the study of quasar properties
dynamical age兲 influence the formation of clusters, but sug- to unlensed X-ray flux levels as low as a few ⫻10⫺15 erg
gested that large tidal dwarf formation may require different s⫺1 cm⫺2 . They presented a comparison between the X-ray
conditions. properties of quasars at redshifts near the peak of their co-
moving number density, thought to have occurred at z⬃ 2,
3.2.2.6 Sloan Digital Sky Survey Schneider, Brandt, postdoc-
and those before and after this era. This comparison may
toral scholar Richards 共now at Princeton University兲, and
provide clues to what caused the dramatic decay of the qua-
undergraduates Reichard and Trump have been using data
sar number density as the Universe expanded. They find a
from the Sloan Digital Sky Survey 共SDSS兲 to investigate
significant correlation between X-ray spectral slope and L X
quasars. Schneider is the Chair of the SDSS Quasar Science
with a Spearman rank correlation coefficient of 0.82 signifi-
Working Group; the main effort of the past year has been the
cant at ⬎99.8 % confidence. Such a correlation does not
production of the second edition of the SDSS Quasar Catalog
exist in nearby z⬍ 0.1 quasars suggesting that quasars at
共Schneider et al. 2003兲. This catalog contains accurate posi-
redshifts near the peak of their number density may have
tions, five band CCD photometry, and digital spectra for
different accretion properties.
16,713 quasars in the SDSS First Data Release. The first
edition of the SDSS Broad Absorption Line Quasar Catalog 3.2.2.8 Galaxy Evolution Gronwall, as a member of the Ad-
共Reichard et al. 2003兲 was the Honors thesis of Reichard. vanced Camera for Surveys 共ACS兲 Instrument Definition
The SDSS quasar team announced the discovery of the Team utilized this new instrument on the Hubble Space Tele-
most distant quasar 共redshift of 6.4兲 in January 2003 共Fan scope to study the evolution of galaxies both in the cluster
et al. 2003兲. Three quasars at redshifts larger than three were and in the field. Recent results include the study of the color-
identified in this paper; the spectra of two of the three qua- magnitude relation in a distant (z⬃1.2) cluster which shows
sars reported in this work were obtained with the Hobby- little or no evolution with respect to local clusters. This im-
Eberly Telescope. The near infrared properties of a set of plies that elliptical galaxies were formed and in place at red-
high-redshift (z⬎4) quasars was presented by Pentericci shifts greater than one 共Blakeslee et al. 2003兲. Other work
et al. 共2003兲. focuses on the study of ACS grism spectra of the Hubble
Since the discovery of ‘‘red quasars’’ in the 1990s, there Deep Field North. The grism spectra are providing redshifts
has been much speculation that current quasar surveys, of emission-line galaxies several magnitudes fainter than
which are primarily based in optical wavelengths, may be those obtained by ground-based spectroscopy. By identifying
missing a significant fraction 共a majority?兲 of the quasar galaxies via their H␣ and 关O II兴-emission they will obtain a
sample ideal for studying the evolution of star-forming gal-
population. The broad wavelength coverage and near-
axies out to z⬃1.5.
infrared sensitivity of the SDSS greatly enhances this sur-
In collaboration with John Salzer 共Wesleyan兲, Gronwall
vey’s ability, compared to most previous optical studies, to
has continued working on the KPNO International Spectro-
detect red quasars 共Richards et al. 2003兲.
scopic Survey 共KISS兲 for nearby emission-line galaxies
3.2.2.7 Active Galaxies and Quasars Chartas in collaboration 共ELGs兲. This is a modern objective-prism survey which
with Brandt and Gallagher reported the discovery of a rela- combines the wide field survey capability of a Schmidt tele-
tivistic X-ray absorbing outflow in the mini-BAL quasar PG scope combined with the deep sensitivity of a CCD detector.
1115⫹080. The XMM-Newton spectrum of PG 1115⫹080 The first survey lists for galaxies selected both in the red
indicates the presence of complex low-energy absorption in 共H␣ ) and the blue 共关O III兴5007兲 have been completed. The
the 0.2–0.6 keV observed energy band and high-energy ab- first blue survey strip covers 117 deg2 and includes 223 ELG
sorption in the 2–5 keV observed energy band. The high- candidates or 1.9 per square degree. The first red
energy absorption is best modeled by two Gaussian absorp- 共H␣ -selected兲 survey strip covers 62 deg2 and includes 1128
tion lines with rest-frame energies of 7.4 keV and 9.5 keV. ELG candidates for a surface density of 18.1 per square de-
Assuming that these two lines are produced by resonant ab- gree. These surface densities are significantly higher than
sorption due to Fe XXV K␣ , they infer that the X-ray absorb- previous surveys of this type. Significant progress on obtain-
ers are outflowing with relativistic velocities of 0.10c and ing follow-up spectroscopy of this sample was made this past
0.34c, respectively. They have also detected significant vari- year utilizing the Hobby-Eberly Telescope to observe severalPENNSYLVANIA STATE UNIVESITY 9
hundred of the faintest objects in the survey. The galaxies transient obtained with the Hobby-Eberly telescope starting
targeted are low-metallicity candidates, and abundance qual- 15.48, 20.31 hours, and 4.84 days after the burst and a spec-
ity spectra of the best candidates from the HET targets will trum obtained with the H. J. Smith 2.7 m Telescope starting
be obtained this coming spring in an attempt to increase the 14.31 hours after the burst. GRB021004 is the first afterglow
numbers of known low-metallicity galaxies. Other ongoing whose spectrum is dominated by absorption lines from high
work with KISS includes: studying the multiwavelength ionization species with multiple velocity components sepa-
properties of KISS ELGs by cross-correlating their survey rated by up to 3000 km/s. They argue that these lines are
lists with existing surveys in the x-ray, radio, and far- likely to come from shells around a massive progenitor star.
infrared, and measuring the chemical properties and star- 3.2.2.11 Quasar Absorption Lines and Galaxy Evolution The
formation rates of these galaxies. Future work plans for intervening quasar absorption line group at Penn State, dur-
studying the multiwavelength properties of star-forming gal- ing the reporting period, included faculty members Charlton
axies using upcoming data from the GALEX and SIRTF and Churchill, graduate students Ding and Narayanan, and
satellites. Gronwall presented results from KISS at the IAU undergraduate students Lynch, Masiero, and Milutinovic.
General Assembly in Sydney, Australia. Several former undergraduate students also published works
3.2.2.9 Intrinsic Quasar Absorption Lines Ganguly 共PSU completed during their time at Penn State. They are listed
graduate student, now a postdoc at the Space Telescope Sci- here along with their graduate institutions: Mellon 共Vir-
ence Institute兲, Masiero 共PSU undergraduate兲, and Charlton ginia兲, Rigby 共Arizona兲, Zonak 共Maryland兲. In August 2003,
published a paper on an intrinsic absorption complex along Churchill began work as an assistant professor at New
the line of sight toward the quasar RXJ 1230.8⫹0115. This Mexico State University.
system shows clear signs of an intrinsic origin: smooth wind- The focus of the quasar absorption line group’s effort has
like profiles, high ionization, and partial coverage of the cen- been to attempt to break the ‘‘code’’ of the spectra by mod-
tral engine. Also, two of the sub-systems are line-locked with eling the multiple chemical transitions observed in various
the third, which is formally classified as a mini-BAL. absorption line systems. The power of this is that it facilitates
Wise 共PSU graduate student兲, Eracleous, Charlton, and detailed studies of the evolution of the interstellar medium,
Ganguly completed a study variability of associate narrow gaseous halos, and high velocity clouds of galaxies. Another
absorption lines, comparing data obtained with FOS to data emphasis of the effort is study of the class of weak Mg II
obtained about 10 years later with STIS. They found that at absorbers, which have near solar metallicity, but are known
least 20% of the associated narrow absorption lines in low not to be within ⬃50 kpc of giant galaxies. These objects are
redshift (z⬍1) quasars are intrinsic. They plan followup surprisingly abundant, with at least 1 million for every giant
studies of some of these objects, to determine the variability galaxy in the universe. The group’s strategy to investigate
timescale and to examine the nature of the change at higher them includes searches for weak Mg II absorbers at very low
resolution. redshifts, considerations of their geometries based on num-
Palma, Ganguly, Charlton, Eracleous, Masiero 共PSU un- bers and inferred phase structures, and simulations of the
dergraduate兲, Ryan Lynch 共PSU undergraduate兲, and Lackey evolution of these intriguing systems.
共PSU undergraduate兲 have nearly completed a search for in- Graduate student, Ding, has led two papers that feature
trinsic absorption in the HST archive of STIS/Echelle quasar detailed studies of strong Mg II absorbers. One features a
spectra. The strategy for the search, which focused on qua- very rich system at z⬃0.93 toward the quasar PG 1206
sars at redshifts less than 1.5, was to identify all doublets in ⫹459, which has a kinematic spread of ⬃1000 km/s. This
the spectra and apply partial coverage analysis to find a system is likely to be due to absorption through three sepa-
lower limit on the number of quasars with intrinsic absorp- rate galaxies, two giants and one dwarf. All three subsystems
tion 共not all intrinsic absorbers will necessarily exhibit par- have multiple phases of gas. The high ionization/low density
phases have similar kinematic spreads to the low ionization/
tial covering兲. A number of intrinsic absorbers, with clear
high density phases. However, in one of the giant galaxy
evidence for partial covering兲 have been identified in this
absorbers the high ionization gas has narrow, distinct com-
study.
ponents, and in the other the high ionization profile struc-
Lackey, Charlton, Eracleous, and Ganguly have been pur-
tures are smooth and reminiscent of those of the Milky Way
suing photoionization models to better understand the physi-
corona. The other paper led by Ding featured the z⬃0.99
cal conditions of intrinsic absorbers. The NV absorption in
system toward PG 1634⫹706, which is noteworthy because
these objects is often quite strong compared to the Lyman-
it is a C IV-deficient, strong Mg II absorber. Ding hypoth-
alpha absorption, and they found that this is primarily an
esized that the system may be C IV-deficient because it has a
effect of partial covering. In fact, many transitions are satu-
low metallicity, component with a large Doppler parameter,
rated, but the partial coverage causes them all to have ap-
which is needed to fit Lyman-alpha and higher order Lyman
proximately the same equivalent width. series lines.
3.2.2.10 Gamma-Ray Burstss Schaefer, Gerardy, Hoflich, Churchill, Mellon, Charlton, and Vogt exploited a unique
Panaitescu, Quimby, Mader, Hill, Kumar, Wheeler, Eracle- opportunity to study a z⫽1.39 damped Lyman-alpha ab-
ous, Sigurdsson, Mészáros, Zhang, Wang, Hessman, and sorber at two different positions, separated by ⬃135 pc. This
Petrosian 共Texas, Penn State, Stanford, Goettingen兲 pub- was possible because of a double-image lensed quasar,
lished an analysis of GRB 021004: a Massive Progenitor Star Q0957⫹561A and B, which lies behind the DLA structure.
Surrounded by Shells. They present spectra of the optical Despite the relatively close lines of sight, there is no direct10 ANNUAL REPORT
connection between the substructure/clouds in the two sight- advanced substantially over the past few years, largely due to
lines. Photoionization models implied individual cloud sizes results from the new generation of X-ray observatories.
of 1-25pc and densities of 2-20 cubic centimeters. The con- X-ray emission has now been detected from more than 80
clusion is that the DLA cloud and those that surround it are such quasars; most detections have been made by Penn State
similar to groupings of cold ISM clouds in the Milky Way. researchers. Recently, Vignali et al. 共2003兲 have reported on
Zonak led a paper that featured a multiple-cloud, weak Chandra and XMM-Newton observations of a sample of 13
Mg II system at z⬃1.04 along the line of sight toward PG quasars at z⬇ 4.7–5.4 mostly taken from the Sloan Digital
1634⫹706. This system is interesting because it has two Sky Survey 共SDSS兲. The present sample complements pre-
separate groupings of low ionization components, separated vious X-ray studies of z⭓4 quasars, in which the majority of
by about 150 km/s, and two separate high ionization compo- the objects are optically more luminous and at lower red-
nents, each offset by ⬃50 km/s from the low ionization re- shifts. All but two of these quasars have been detected in the
gions. The metallicities of the low ionization components are X-ray band, thus doubling the number of z⭓4.8 X-ray de-
fairly low, about 3% of the solar value, and the broad, high tected quasars; the two non-detections are likely to be due to
ionization components apparently have a somewhat higher a short exposure time in one case and to the presence of
metallicity. The various inferred properties suggested their intrinsic absorption in the other. Vignali et al. 共2003兲 con-
favored model in which the two subsystems are produced by firm and extend to the highest redshifts the presence of a
condensed clouds far out in the opposite extremes of a multi- correlation between AB1450 magnitude and soft X-ray flux
layer dwarf galaxy superwind. for z⭓4 quasars, and the presence of a steeper optical-to-X-
Efforts to understand the mysterious, single-cloud weak ray spectral energy distribution for high-luminosity, high-
Mg II absorbers included a detailed study of the phase struc- redshift quasars than for lower-luminosity, lower-redshift
ture of three systems at z⬃1 along the line of sight toward quasars. The second effect is likely due to a known luminos-
PG 1634⫹706. Each absorber had a broader C IV compo- ity correlation, whose significance has been confirmed via
nent centered on its Mg II component, suggested a lower partial correlation analysis. The joint ⬇2.5–36 keV
density, but kinematically related gaseous phase. Two of the rest-frame spectrum of the z⬎4.8 SDSS quasars observed
three absorbers had one or more offset C IV components as thus far by Chandra is well parameterized by a power law
⫹0.31
well, at velocities at which Mg II was not detected. The with photon index ⌫⫽1.84⫺0.30 ; this photon index is consis-
inferred sizes show that the region producing high ionization tent with those of z⬇ 0–3 quasars and that obtained from
absorption is larger/thicker than the 1-100 pc regions that joint spectral fitting of z⬇ 4.1–4.5 optically luminous Palo-
produce the Mg II absorption. In two of the three systems, mar Digital Sky Survey quasars. No evidence for widespread
the metallicity of the Mg II phase was greater than solar. intrinsic X-ray absorption has been found.
Recently, Milutinovic, Charlton, Rigby, Ding, Masiero,
and Palma have conducted a simple survey of the high reso- 3.2.2.13 X-ray Spectroscopic and Variability Studies of
lution HST/STIS Echelle archive, which nonetheless has led Nearby Active Galaxies Immler et al. 共2003兲 have reported
to some fundamental conclusions. The simplest geometry for on an X-ray observation of the Seyfert 1.5 galaxy Markarian
the Mg II and C IV components of single-cloud, weak Mg II 6 obtained with the EPIC instruments onboard XMM-
absorbers has the Mg II in a small spherical cloud embedded Newton. Archival BeppoSAX PDS data from 18–120 keV
in a larger C IV region. This, however, is ruled out by Mi- were also used to constrain the underlying hard power-law
lutinovic’s recent study, because there are fewer C IV-only continuum. The results from spectral analyses generally fa-
systems found in the archive than there are systems with vor a double partial-covering model, although other spectral
both low ionization absorption and C IV absorption. This models such as absorption by a mixture of partially ionized
suggests a sheetlike geometry, which may have a natural and neutral gas cannot be firmly ruled out. The best-fitting
connection with the cosmic web, seen in cosmological struc- model consists of a power law with a photon index of ⌫
⫹0.22
ture formation simulations. A manuscript is in preparation. ⫽1.81⫺0.20 and partial covering with large column densities
Narayanan 共graduate student兲 has conducted a survey, up to N H⬃1023 cm⫺2 . A narrow emission line consistent
⫹0.03
looking for the analogs of weak Mg II absorbers at low red- with Fe K␣ fluorescence at 6.45⫺0.04 keV is also detected
⫹26
shift by searching for Si II and C II absorption, which would with an equivalent width of 93⫺20 eV. Joint analyses of
be covered in HST/STIS E140M spectra. He has found sev- XMM-Newton, ASCA, and BeppoSAX data further provide
eral such absorbers, which are excellent candidates for fol- evidence for both spectral variability 共a factor of ⬃2 change
lowup imaging studies. He plans a formal analysis to deter- in absorbing column兲 and absorption-corrected flux varia-
mine the number of weak Mg II absorbers per unit redshift. tions 共by ⬃60%兲 during the ⬃4 year period probed by the
He has also explored photoionization models of these sys- observations.
tems. He conducted simulations to explore the evolution of 3.2.2.14 X-ray Studies of Starburst Galaxies Bauer & Brandt
the systems due to the diminishing extragalactic background 共2003兲 have presented a Chandra and HST study of IC 10
radiation. They are expected to have increasing importance X-1, the most luminous X-ray binary in the closest starburst
of their C IV phases relative to the Mg II phases, and to even galaxy to the Milky Way. The new hard X-ray observation of
in some cases transition from single-cloud to multiple-cloud X-1 confirms that it has an average 0.5–10 keV luminosity
weak Mg II absorbers. of 1.5⫻1038 erg s⫺1 , is strongly variable 共a factor of ⬇2 in
3.2.2.12 X-ray Studies of Luminous High-Redshift Quasars ⬍3 ks兲, and is spatially coincident with the Wolf-Rayet
X-ray studies of luminous high-redshift (z⬎4) quasars have 共WR兲 star 关MAC92兴 17A in IC 10. The spectrum of X-1 isYou can also read
