Search Publications
X-Ray Properties of Intermediate-Redshift Groups of Galaxies
Mulchaey, John S.; Rosati, Piero; Lubin, Lori M. +2 more
We have undertaken a multiwavelength project to study the relatively unknown properties of groups and poor clusters of galaxies at intermediate redshifts. In this paper, we describe the XMM-Newton observations of six X-ray-selected groups with 0.2<z<0.6. The X-ray properties of these systems are generally in good agreement with the propertie…
Multiwavelength Variability of the Magnetar 4U 0142+61
Durant, Martin; van Kerkwijk, Marten H.
We have collected data spanning seven years of observations of the magnetar 4U 0142+61 in the infrared, optical, and soft X-rays. These combine our own observations and analysis of archival data. We find that the source is variable in the optical, in contrast to what had been previously reported, that the K-band flux can vary by over a magnitude o…
Can Ejecta-dominated Supernova Remnants be Typed from Their X-Ray Spectra? The Case of G337.2-0.7
Gelfand, Joseph D.; Hughes, John P.; Gaensler, B. M. +3 more
In this paper we use recent X-ray and radio observations of the ejecta-rich Galactic SNR G337.2-0.7 to determine properties of the SN explosion that formed this source. H I absorption measurements from ATCA constrain the distance to G337.2-0.7 to lie between 2.0+/-0.5 and 9.3+/-0.3 kpc. Combined with a clear radio image of the outer blast wave, th…
Evidence for Surface Cooling Emission in the XMM-Newton Spectrum of the X-Ray Pulsar PSR B2334+61
Cropper, M.; McGowan, K. E.; Zane, S. +2 more
We report on the first XMM-Newton observation of the Vela-like pulsar PSR B2334+61. Spectral analysis reveals soft X-ray emission, with the bulk of the photons emitted at energies below ~1.5 keV. We find that the spectrum has a thermal origin and is well-fitted with either a blackbody or a magnetized, pure H atmospheric model. In the latter case, …
The Redshift Distribution of Distant Supernovae and Its Use in Probing Reionization
Johnson, Benjamin D.; Haiman, Zoltán; Mesinger, Andrei
We model the number of detectable supernovae (SNe) as a function of redshift at different flux thresholds, making use of the observed properties of local SNe, such as their light curves, fiducial spectra, and peak magnitude distributions. We assume that the star formation rate (SFR) at high redshift traces the formation rate of dark matter halos. …
Rotation of Solar Corona from Tracking of Coronal Bright Points
Pevtsov, Alexei A.; Sattarov, Isroil; Karachik, Nina
An automated procedure for identification of coronal bright points is applied to selected EIT images observed at various phases of the solar cycle. The procedure finds about 400 bright points on a single EIT image observed at 195 Å. The positions of the bright points are tracked to study the profile of solar rotation in the solar corona. It is sho…
Deep Photometry of Andromeda Reveals Striking Similarities in the Tidal Stream and Spheroid Populations
Ferguson, Henry C.; Brown, Thomas M.; Rich, R. Michael +5 more
We present a color-magnitude diagram (CMD) for a field in the giant tidal stream of the Andromeda galaxy (M31). These observations, taken with the Advanced Camera for Surveys on the Hubble Space Telescope, are 50% complete at V~30 mag, reaching 1 mag below the oldest main-sequence turnoff. Striking similarities between the stream and a previous sp…
A Hubble Space Telescope Advanced Camera for Surveys Search for Brown Dwarf Binaries in the Pleiades Open Cluster
Martín, E. L.; Bouy, H.; Bouvier, J. +5 more
We present the results of a high-resolution imaging survey for brown dwarf binaries in the Pleiades open cluster. The observations were carried out with the Advanced Camera for Surveys (Pavlovsky and coworkers) on board the Hubble Space Telescope. Our sample consists of 15 bona fide brown dwarfs. We confirm two binaries and detect their orbital mo…
Weak-lensing Detection at z ~ 1.3: Measurement of the Two Lynx Clusters with the Advanced Camera for Surveys
Ford, H. C.; Jee, M. J.; Illingworth, G. D. +4 more
We present a Hubble Space Telescope Advanced Camera for Surveys (ACS) weak-lensing study of RX J0849+4452 and RX J0848+4453, the two most distant (at z=1.26 and 1.27, respectively) clusters yet measured with weak lensing. The two clusters are separated by ~4' from each other and appear to form a supercluster in the Lynx field. Using our deep ACS i…
Multiwavelength Observations of EXO 0748-676. I. Reprocessing of X-Ray Bursts
Charles, P. A.; Horne, Keith; O'Brien, K. +5 more
We present high time-resolution multiwavelength observations of X-ray bursts in the low-mass X-ray binary UY Vol. Strong reprocessed signals are present in the ultraviolet and optical, lagged and smeared with respect to the X-rays. The addition of far-ultraviolet coverage for one burst allows much tighter constraints on the temperature and geometr…