Search Publications
Star Formation and UV colors of the Brightest Cluster Galaxies in the Representative XMM-Newton Cluster Structure Survey
Donahue, Megan; Voit, G. Mark; Pierini, Daniele +8 more
We present UV broadband photometry and optical emission-line measurements for a sample of 32 brightest cluster galaxies (BCGs) in clusters of the Representative XMM-Newton Cluster Structure Survey (REXCESS) with z = 0.06-0.18. The REXCESS clusters, chosen to study scaling relations in clusters of galaxies, have X-ray measurements of high quality. …
Identification of the X-ray Thermal Dominant State in an Ultraluminous X-ray Source in M82
Feng, Hua; Kaaret, Philip
The thermal dominant state in black hole binaries (BHBs) is well understood but rarely seen in ultraluminous X-ray sources (ULXs). Using simultaneous observations of M82 with Chandra and XMM-Newton, we report the first likely identification of the thermal dominant state in a ULX based on the disappearance of X-ray oscillations, low timing noise, a…
A Massive Runaway Star from 30 Doradus
van Loon, J. Th.; Howarth, I. D.; Massa, D. +7 more
We present the first ultraviolet (UV) and multi-epoch optical spectroscopy of 30 Dor 016, a massive O2-type star on the periphery of 30 Doradus in the Large Magellanic Cloud. The UV data were obtained with the Cosmic Origins Spectrograph on the Hubble Space Telescope as part of the Servicing Mission Observatory Verification program after Servicing…
Microwave Quasi-Periodic Pulsations in Multi-timescales Associated with a Solar Flare/CME Event
Tan, Baolin; Tan, Chengming; Zhang, Yin +1 more
Microwave observations of quasi-periodic pulsations (QPPs) in multi-timescales at the Solar Broadband Radio Spectrometer in Huairou (SBRS/Huairou) on 2006 December 13 are confirmed to be associated with an X3.4 flare/coronal mass ejection (CME) event. It is most remarkable that the timescales of QPPs are distributed in a broad range from hectoseco…
The Advanced Camera for Surveys Fornax Cluster Survey. VII. Half-light Radii of Globular Clusters in Early-type Galaxies
Jordán, Andrés; Infante, Leopoldo; Côté, Patrick +6 more
We measure the half-light radii of globular clusters (GCs) in 43 galaxies from the Advanced Camera for Surveys (ACS) Fornax Cluster Survey. We use these data to extend previous work in which the environmental dependencies of the half-light radii of GCs in early-type galaxies in the ACS Virgo Cluster Survey were studied, and a corrected mean half-l…
On a New Near-Infrared Method to Estimate the Absolute Ages of Star Clusters: NGC 3201 as a First Test Case
Walker, A. R.; Prada Moroni, P. G.; Degl'Innocenti, S. +25 more
We present a new method to estimate the absolute ages of stellar systems. This method is based on the difference in magnitude between the main-sequence turnoff (MSTO) and a well-defined knee located along the lower main sequence (MSK). This feature is caused by the collisionally induced absorption of molecular hydrogen, and it can easily be identi…
Revisiting the Parallax of the Isolated Neutron Star RX J185635-3754 Using HST/ACS Imaging
Neuhäuser, R.; Walter, F. M.; Lattimer, J. M. +3 more
We have redetermined the parallax and proper motion of the nearby isolated neutron star RX J185635-3754. We used eight observations with the high-resolution camera of the HST/ACS taken from 2002 through 2004. We performed the astrometric fitting using five independent methods, all of which yielded consistent results. The mean estimate of the paral…
Star Formation Efficiency in the Barred Spiral Galaxy NGC 4303
Momose, Rieko; Koda, Jin; Sawada, Tsuyoshi +1 more
We present new 12CO (J = 1 - 0) observations of the barred galaxy NGC 4303 using the Nobeyama 45 m telescope (NRO45) and the Combined Array for Research in Millimeter-wave Astronomy (CARMA). The Hα images of barred spiral galaxies often show active star formation in spiral arms, but less so in bars. We quantify the difference by measuri…
Identification of Faint Chandra X-ray Sources in the Core-collapsed Globular Cluster NGC 6397: Evidence for a Bimodal Cataclysmic Variable Population
Anderson, Jay; Bogdanov, Slavko; Heinke, Craig O. +6 more
We have searched for optical identifications for 79 Chandra X-ray sources that lie within the half-mass radius of the nearby, core-collapsed globular cluster NGC 6397, using deep Hubble Space Telescope Advanced Camera for Surveys Wide Field Channel imaging in Hα, R, and B. Photometry of these images allows us to classify candidate counterparts bas…
Rapid Cooling of the Neutron Star in the Quiescent Super-Eddington Transient XTE J1701-462
Homan, Jeroen; Cackett, Edward M.; Fridriksson, Joel K. +7 more
We present Rossi X-Ray Timing Explorer and Swift observations made during the final three weeks of the 2006-2007 outburst of the super-Eddington neutron star (NS) transient XTE J1701-462, as well as Chandra and XMM-Newton observations covering the first ≃800 days of the subsequent quiescent phase. The source transitioned quickly from active accret…