924 citations · 10.6k across the 203 of their papers we have counts for
33 papers · 1 filter
Detection of the second eclipsing high mass X-ray binary in M 33
W. Pietsch, F. Haberl, T. J. Gaetz +7
Chandra data of the X-ray source [PMH2004] 47 were obtained in the ACIS Survey of M 33 (ChASeM33) in 2006. During one of the observations, the source varied from a high state to a…
An extended dust disk in a spiral galaxy; An occulting galaxy pair in ANGST
B. W. Holwerda, W. C. Keel, B. Williams +2
We present an analysis of an occulting galaxy pair, serendipitously discovered in ACS Nearby Galaxy Survey Treasury (ANGST) observations of NGC 253 taken with Hubble Space Telescop…
The ACS Nearby Galaxy Survey Treasury I. The Star Formation History of the M81 Outer Disk
Benjamin F. Williams, Julianne J. Dalcanton, Anil C. Seth +16
The ACS Nearby Galaxy Survey Treasury (ANGST) is a large Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) treasury program to obtain resolved stellar photometry for a…
The ACS Nearby Galaxy Survey Treasury II. Young Stars and their Relation to Halpha and UV Emission Timescales in the M81 Outer Disk
Stephanie M. Gogarten, Julianne J. Dalcanton, Benjamin F. Williams +11
We have obtained resolved stellar photometry from Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) observations of a field in the outer disk of M81 as part of the ACS…
New XMM-Newton analysis of three bright X-ray sources in M31 globular clusters, including a new black hole candidate
R. Barnard, H. Stiele, D. Hatzidimitriou +6
We present detailed analysis of three globular cluster X-ray sources in the XMM-Newton extended survey of M31. The X-ray counterpart to the M31 globular cluster Bo 45 (XBo 45) was…
Revised bolometric corrections and interstellar extinction coefficients for the ACS and WFPC2 photometric systems
L. Girardi, J. Dalcanton, B. Williams +8
We present extensive tables of bolometric corrections and interstellar extinction coefficients for the WFPC2 and ACS (both WFC and HRC) photometric systems. They are derived from s…
The Chandra ACIS Survey of M33 (ChASeM33): Transient X-ray Sources Discovered in M33
Benjamin F. Williams, Terrance J. Gaetz, Frank Haberl +7
The Chandra ACIS Survey of M33 (ChASeM33) has acquired 7 fields of ACIS data covering M33 with 200 ks of exposure in each field. A catalog from the first 10 months of data, along w…
Chandra ACIS Survey of M33 (ChASeM33): A First Look
Paul P. Plucinsky, Benjamin Williams, Knox S. Long +22
We present an overview of the Chandra ACIS Survey of M33 (ChASeM33): A Deep Survey of the Nearest Face-on Spiral Galaxy. The 1.4 Ms survey covers the galaxy out to $R \approx 18\ar…
Chandra ACIS Survey of M33 (ChASeM33): X-ray Imaging Spectroscopy of M33SNR21, the Brightest X-ray Supernova Remnant in M33
Terrance J. Gaetz, William P. Blair, John P. Hughes +11
We present and interpret new X-ray data for M33SNR21, the brightest X-ray supernova remnant (SNR) in M33. The SNR is in seen projection against (and appears to be interacting with)…
The Metallicity Distribution of Intracluster Stars in Virgo
Benjamin F. Williams, Robin Ciardullo, Patrick R. Durrell +11
We have used the Hubble Space Telescope's Advanced Camera for Surveys (ACS) to detect and measure ~5300 stars in a single intracluster field in the Virgo Cluster. By performing F60…
Virgo's Intracluster Globular Clusters as Seen by the Advanced Camera for Surveys
Benjamin F. Williams, Robin Ciardullo, Patrick R. Durrell +11
We report the discovery of 4 candidate intracluster globular clusters (IGCs) in a single deep HST ACS field of the Virgo Cluster. We show that each cluster is roughly spherical, ha…
A Soft X-ray Transient in the M31 Bulge
Benjamin F. Williams, Michael R. Garcia, Jeffrey E. McClintock +2
We have examined a probable soft X-ray transient source in the M31 bulge at R.A.=0:42:41.814 +/- 0.08", Dec. = 41:16:35.86 +/- 0.07". On the three occasions we observed the source,…
Chandra and Hubble Study of a New Transient X-ray Source in M31
Benjamin F. Williams, Michael R. Garcia, Jeffrey E. McClintock +2
We present X-ray and optical observations of a new transient X-ray source in M31 first detected 23-May-2004 at R.A.=00:43:09.940 +/- 0.65'', Dec.=41:23:32.49 +/- 0.66''. The X-ray…
A Potential Supernova Remnant/X-ray Binary Association in M31
Benjamin F. Williams, Robin Barnard, Michael R. Garcia +3
The well-studied X-ray/Optical/Radio supernova remnant DDB 1-15 (CXOM31 J004327.8+411829; r3-63) in M31 has been investigated with archival XMM-Newton and Chandra observations. The…
Optical Constraints on an X-ray Transient Source in M31
Benjamin F. Williams, Michael R. Garcia, Frank A. Primini +2
We have detected a transient X-ray source in the M31 bulge through a continuing monitoring campaign with the Chandra ACIS-I camera. The source was detected at R.A.=00:42:33.428 +/-…
An X-ray Transient and Optical Counterpart in the M31 Bulge
Benjamin F. Williams, Michael R. Garcia, Jeffrey E. McClintock +3
We have obtained snapshot images of a transient X-ray source in M31 from Chandra ACIS-I and the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The Chandra position…
Variable Star Candidates in an ACS Field of M31
Benjamin F. Williams
A search for variable stars is performed using two epochs of Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) imaging data for a 9.28 square arcminute portion of M31.…
A Possible Detection of M31* with Chandra
M. R. Garcia, B. F. Williams, F. Yuan +5
Two independent sets of Chandra and HST images of the nuclear region of M31 allow registration of X-ray and optical images to 0.1''. This registration shows that none of the bright…
Discovery of an X-ray Nova in M31
Benjamin F. Williams, Michael R. Garcia, Albert K. H. Kong +2
We have obtained snapshot images of an X-ray nova in M31 from Chandra ACIS-I and the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The Chandra position of the X-r…
X-ray/Optical/Radio Observations of a Resolved Supernova Remnant in NGC 6822
A. K. H. Kong, L. O. Sjouwerman, B. F. Williams
The supernova remnant (SNR), Ho 12, in the center of the dwarf irregular galaxy NGC 6822 was previously observed at X-ray, optical, and radio wavelengths. By using archival Chandra…
Two New X-ray/Optical/Radio Supernova Remnants in M31
B. F. Williams, L. O. Sjouwerman, A. K. H. Kong +3
We compare a deep (37 ks) Chandra ACIS-S image of the M31 bulge to Local Group Survey narrow-band optical data and Very Large Array (VLA) radio data of the same region. Our precise…
Why are X-ray sources in the M31 Bulge so close to Planetary Nebulae?
Benjamin F. Williams, Michael R. Garcia, Jeffrey E. McClintock +1
We compare a deep (37 ks) Chandra ACIS-S image of the M31 bulge to deep [O III] Local Group Survey data of the same region. Through precision image alignment using globular cluster…
Imaging and Demography of the Host Galaxies of High-Redshift Type Ia Supernovae
Benjamin F. Williams, Craig J. Hogan, Brian Barris +24
We present the results of a study of the host galaxies of high redshift Type Ia supernovae (SNe Ia). We provide a catalog of 18 hosts of SNe Ia observed with the Hubble Space Teles…
The Recent Star Formation History of the M31 Disk
Benjamin F. Williams
The star formation history of the northern and southern M31 disk is measured using samples of BV photometry for 4' X 4' regions taken from the KPNO/CTIO Local Group Survey (Massey…