Discovery of an optical counterpart to the hyperluminous X-ray source in ESO 243-49 (2009)
Soria, Roberto, Hau, George K. T., Graham, Alister W., Kong, Albert K. H., Kuin, N. Paul M., Li, I-Hui, ...
The existence of black holes of masses ~ 10^3-10^4 Msun has important implications for the formation and evolution of star clusters and galaxies. The strongest candidate so far is the hyperluminous...
X-ray and Optical Study of Low Core Density Globular Clusters NGC6144 and E3 (2009)
Lan, Shih Hao, Kong, Albert K. H., Verbunt, Frank, Lewin, Walter H. G., Bassa, Cees, Anderson, Scott F., ...
We report on the Chandra X-ray Observatory and Hubble Space Telescope observation of two low core density globular clusters, NGC6144 and E3. By comparing the number of X-ray sources inside the...
X-ray Sources and Their Optical Counterparts in the Galactic Globular Cluster M12 (NGC 6218) (2009)
Lu, Ting-Ni, Kong, Albert K. H., Bassa, Cees, Verbunt, Frank, Lewin, Walter H. G., Anderson, Scott F., ...
We study a Chandra X-ray Observatory ACIS-S observation of the Galactic globular clusterM12. With a 26 ks exposure time, we detect 6 X-ray sources inside the half-mass radius (2.16 arcminutes) of...
GX 9+9: Variability of the X-Ray Orbital Modulation (2009)
Harris, Robert J., Levine, Alan M., Durant, Martin, Kong, Albert K. H., Charles, Phil, Shahbaz, Tariq
Results of observations of the Galactic bulge X-ray source GX 9+9 by the All-Sky Monitor (ASM) and Proportional Counter Array (PCA) onboard the Rossi X-ray Timing Explorer are presented. The ASM...
The Long-Term Variability of the X-Ray Sources in NGC 6946 and NGC 4485/4490 (2008)
Fridriksson, Joel K., Homan, Jeroen, Lewin, Walter H. G., Kong, Albert K. H., Pooley, David
We analyze data from five Chandra observations of the spiral galaxy NGC 6946 and from three Chandra observations of the irregular/spiral interacting galaxy pair NGC 4485/4490, with an emphasis on...
Kong, Albert K. H., Miller, Jon M., Mendez, Mariano, Cottam, Jean, Lewin, Walter H. G., Paerels, Frederik, ...
During a 200 ks observation with the XMM-Newton Reflection Grating Spectrometer, we detected 16 type-I X-ray bursts from GS 1826-24. We combined the burst spectra in an attempt to measure the...
High Resolution X-Ray Imaging of the Center of IC342 (2007)
Mak, Daisy S. Y., Pun, Chun. S. J., Kong, Albert K. H.
We presented the result of a high resolution (FWHM~0.5'') 12 ks Chandra HRC-I observation of the starburst galaxy IC342 taken on 2 April 2006. We identified 23 X-ray sources within the central 30' x...
X-ray Localization of the Globular Cluster G1 with XMM-Newton (2007)
We present an accurate X-ray position of the massive globular cluster G1 by using XMM-Newton and the Hubble Space Telescope (HST). The X-ray emission of G1 has been detected recently with XMM-Newton....
The Spectrum of the Black Hole X-Ray Nova V404 Cygni in Quiescence as Measured by XMM-Newton (2007)
Bradley, Charles K., Hynes, Robert I., Kong, Albert K. H., Haswell, C. A., Casares, J., Gallo, E.
We present XMM-Newton observations of the black hole X-ray nova V404 Cyg in quiescence. Its quiescent spectrum can be best fitted by a simple power law with slope Γ~2. The spectra are consistent...
A potential supernova remnant-x-ray binary association in M31 (2005)
Williams, Benjamin F., Barnard, Robin, Garcia, Michael R., Kolb, U., Osborne, J.P., Kong, Albert K.H.
The well-studied X-ray/optical/radio supernova remnant (SNR) DDB 1-15 (CXOM31 J004327.8+411829; r3-63) in M31 has been investigated with archival XMM-Newton and Chandra observations. The timing data...
A Potential Supernova Remnant/X-ray Binary Association in M31 (2005)
Williams, Benjamin F., Barnard, Robin, Garcia, Michael R., Kolb, U., Osborne, J. P., Kong, Albert K. H.
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 timing data from...
An X-ray Transient and Optical Counterpart in the M31 Bulge (2005)
Williams, Benjamin F., Garcia, Michael R., McClintock, Jeffrey E., Kong, Albert K. H., Primini, Frank A., Murray, Stephen S.
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 of the X-ray nova...
Discovery of an X-ray Nova in M31 (2004)
Williams, Benjamin F., Garcia, Michael R., Kong, Albert K. H., Primini, Frank A., Murray, Stephen S.
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-ray nova was...
Why are X-ray sources in the M31 Bulge so close to Planetary Nebulae? (2004)
Williams, Benjamin F., Garcia, Michael R., McClintock, Jeffrey E., Kong, Albert K. H.
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 X-ray sources, we...
A Synoptic X-ray Study of M31 with the Chandra-HRC (2003)
Williams, Benjamin F., Garcia, Michael R., Kong, Albert K. H., Primini, Frank A., King, A. R., Di Stefano, Rosanne, ...
We have obtained 17 epochs of Chandra High Resolution Camera (HRC) snapshot images, each covering most of the M31 disk. The data cover a total baseline of 2.5 years and contain a mean effective...
Chandra studies of the X-ray point source luminosity functions of M31 (2003)
Kong, Albert K. H., DiStefano, Rosanne, Garcia, Michael R., Greiner, Jochen
XMM-Newton observations of the spiral galaxy M74 (NGC 628) (2002)
Soria, Roberto, Kong, Albert K. H.
The face-on spiral galaxy M74 (NGC 628) was observed by XMM on 2002 February 2. In total, 21 sources are found in the inner 5' from the nucleus (after rejection of a few sources associated to...