Search Publications
Precise Measurement of the Spin Parameter of the Stellar-Mass Black Hole M33 X-7
McClintock, Jeffrey E.; Liu, Jifeng; Davis, Shane W. +2 more
In prior work, Chandra and Gemini-North observations of the eclipsing X-ray binary M33 X-7 have yielded measurements of the mass of its black hole primary and the system's orbital inclination angle of unprecedented accuracy. Likewise, the distance to the binary is known to a few percent. In an analysis based on these precise results, 15 Chandra an…
Hubble Space Telescope Morphologies of Local Lyman Break Galaxy Analogs. I. Evidence for Starbursts Triggered by Merging
Charlot, Stéphane; Aloisi, Alessandra; Heckman, Timothy M. +10 more
Heckman and coworkers used the GALEX UV imaging survey to show that there exists a rare population of nearby compact UV-luminous galaxies (UVLGs) that closely resemble high-redshift Lyman break galaxies (LBGs). We present HST images in the UV, optical, and Hα and resimulate them at the depth and resolution of the GOODS/UDF fields to show that the …
Are Optically Selected Quasars Universally X-Ray Luminous? X-Ray-UV Relations in Sloan Digital Sky Survey Quasars
Brandt, W. N.; Schneider, Donald P.; Gibson, Robert R.
We analyze archived Chandra and XMM-Newton X-ray observations of 536 Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) quasars (QSOs) at 1.7 <= z<= 2.7 in order to characterize the relative UV and X-ray spectral properties of QSOs that do not have broad UV absorption lines (BALs). We constrain the fraction of X-ray-weak, non-BAL QSOs and …
Reaching the End of the White Dwarf Cooling Sequence in NGC 6791
Anderson, Jay; Salaris, Maurizio; Bedin, Luigi R. +4 more
We present new observations of the white dwarf sequence of the old open cluster NGC 6791. The brighter peak previously observed in the white dwarf luminosity function (WDLF) is now better delineated, and the second, fainter peak that we suggested earlier is now confirmed. A careful study suggests that we have reached the end of the WD sequence. Th…
AMUSE-Virgo. I. Supermassive Black Holes in Low-Mass Spheroids
Treu, Tommaso; Marshall, Philip J.; Antonucci, Robert +3 more
We present the first results from the AGN Multiwavelength Survey of Early-Type Galaxies in the Virgo Cluster (AMUSE-Virgo). This large program targets 100 early-type galaxies with the Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory and the Multiband Imaging Photometer on board the Spitzer Space Telescope, with the aim of p…
INTEGRAL SPI All-Sky View in Soft Gamma Rays: A Study of Point-Source and Galactic Diffuse Emission
Bouchet, L.; Terrier, R.; Diehl, R. +4 more
We have processed the data accumulated with the INTEGRAL SPI instrument over 4 years (~51 Ms) to study the morphology of the Galactic "diffuse" emission in the 20 keV to 8 MeV energy range. To achieve this, we simultaneously derived an all-sky census of emitting sources and images of the Galactic ridge (GR) emission. In the central radian, the res…
A Precise Proper Motion for the Crab Pulsar, and the Difficulty of Testing Spin-Kick Alignment for Young Neutron Stars
Anderson, J.; Chatterjee, S.; Kaplan, D. L. +1 more
We present a detailed analysis of archival Hubble Space Telescope data that we use to measure the proper motion of the Crab pulsar, with the primary goal of comparing the direction of its proper motion with the projected axis of its pulsar wind nebula (the projected spin axis of the pulsar). We demonstrate that our measurement, using 47 observatio…
Effects of Dust Geometry in Lyα Galaxies at z = 4.4
Finkelstein, Steven L.; Malhotra, Sangeeta; Grogin, Norman +2 more
Equivalent widths (EWs) observed in high-redshift Lyα galaxies could be stronger than the EW intrinsic to the stellar population if dust is present residing in clumps in the interstellar medium (ISM). In this scenario, continuum photons could be extinguished, while the Lyα photons would be resonantly scattered by the clumps, eventually escaping th…
Hinode, TRACE, SOHO, and Ground-based Observations of a Quiescent Prominence
Heinzel, P.; Anzer, U.; Golub, L. +10 more
A quiescent prominence was observed by several instruments on 2007 April 25. The temporal evolution was recorded in Hα by the Hinode SOT, in X-rays by the Hinode XRT, and in the 195 Å channel by TRACE. Moreover, ground-based observatories (GBOs) provided calibrated Hα intensities. Simultaneous extreme-UV (EUV) data were also taken by the Hinode EI…
A Population of Massive and Evolved Galaxies at z gtrsim 5
Panagia, N.; Dickinson, M.; Ferguson, H. C. +4 more
We report results from a search for massive and evolved galaxies at z gtrsim 5 in the GOODS southern field. Combining HST ACS, VLT ISAAC, and Spitzer IRAC broadband photometric data, we develop a color selection technique to identify candidates for being evolved galaxies at high redshifts. The color selection is primarily based on locating the Bal…