Search Publications
The Space Motion of the Globular Cluster NGC 6397
Anderson, Jay; Lépine, Sébastien; Rich, R. Michael +12 more
As a by-product of high-precision, ultradeep stellar photometry in the Galactic globular cluster NGC 6397 with the Hubble Space Telescope, we are able to measure a large population of background galaxies whose images are nearly pointlike. These provide an extragalactic reference frame of unprecedented accuracy, relative to which we measure the mos…
A Probabilistic Approach to Classifying Supernovae Using Photometric Information
Kuznetsova, Natalia V.; Connolly, Brian M.
This paper presents a novel method for determining the probability that a supernova candidate belongs to a known supernova type (such as Ia, Ibc, IIL, etc.) using its photometric information alone. It is validated with Monte Carlo simulations, and both space- and ground-based data. We examine the application of the method to well-sampled as well a…
Warm-Hot Intergalactic Medium Associated with the Coma Cluster
Finoguenov, A.; Mitsuda, K.; Tamura, T. +4 more
Hydrodynamic simulations predict that low-redshift baryons are predominantly in a warm-hot intergalactic medium (WHIM), which should exhibit absorption and emission lines in the soft X-ray region. The WHIM is predicted to be most dense around clusters of galaxies. We present our XMM-Newton RGS observations of X Comae, an active galactic nucleus be…
Chandra Observations of the Eagle Nebula. I. Embedded Young Stellar Objects near the Pillars of Creation
Linsky, Jeffrey L.; Andersen, Morten; Gagné, Marc +2 more
We present and analyze the first high-resolution X-ray images ever obtained of the Eagle Nebula star-forming region. On 2001 July 30 the Chandra X-Ray Observatory obtained a 78 ks image of the Eagle Nebula (M16) that includes the core of the young galactic cluster NGC 6611 and the dark columns of dust and cold molecular gas in M16 known as the ``P…
The Ultraluminous X-Ray Sources Near the Center of M82
Pun, C. S. J.; Kong, A. K. H.; Yang, Y. J. +2 more
We report the identification of a recurrent ultraluminous X-ray source (ULX), a highly absorbed X-ray source (possibly a background AGN), and a young supernova remnant near the center of the starburst galaxy M82. From a series of Chandra observations taken from 1999 to 2005, we found that the transient ULX first appeared in 1999 October. The sourc…
The Spectrum of the Black Hole X-Ray Nova V404 Cygni in Quiescence as Measured by XMM-Newton
Kong, Albert K. H.; Casares, J.; Haswell, C. A. +3 more
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 with that expected for the advection-dominated accretion flow (ADAF). V404 Cyg was roughly equal in luminosity compared to the previous observation of Cha…
The Young Cluster Population of M82 Region B
O'Connell, R. W.; Bastian, N.; Larsen, S. S. +6 more
We present observations obtained with the Advanced Camera for Surveys on board the Hubble Space Telescope of the ``fossil'' starburst region B in the nearby starburst galaxy M82. By comparing UBVI photometry with models, we derive ages and extinctions for 35 U-band-selected star clusters. We find that the peak epoch of cluster formation occurred ~…
A Radio through X-Ray Study of the Hot Spots, Active Nucleus, and Environment of the Nearby FR II Radio Galaxy 3C 33
Hardcastle, M. J.; Croston, J. H.; Birkinshaw, M. +4 more
We present results from Chandra ACIS-S, Spitzer, XMM-Newton, HST, and VLA observations of the radio hot spots, extended environment, and nucleus of the nearby (z=0.0597) FR II radio galaxy 3C 33. This is a relatively low power FR II radio galaxy, so we expect, a priori, to detect a significant X-ray synchrotron component to the emission from the h…
Three-dimensional Tomographic Analysis of a High-Cadence LASCO-C2 Polarized Brightness Sequence
Frazin, Richard A.; Kamalabadi, Farzad; Vásquez, Alberto M. +1 more
We present the first 3D tomographic reconstructions of the coronal electron density from an extended, high-cadence sequence of images of the corona's polarized brightness (pB). While the standard LASCO synoptic sequence is only 1 pB image per day, during the 14 day period covering 2006 June 9-22, the C2 coronagraph took about 6.5 pB images per day…
Imaging of the Stellar Population of IC 10 with Laser Guide Star Adaptive Optics and the Hubble Space Telescope
Graham, James R.; Vacca, William D.; Sheehy, Christopher D.
We present adaptive optics (AO) images of the central starburst region of the dwarf irregular galaxy IC 10. The Keck II telescope laser guide star was used to achieve near diffraction-limited performance at H and K' (Strehl ratios of 18% and 32%, respectively). The images are centered on the putative Wolf-Rayet (W-R) object [MAC92]24. W…