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Digital Access to a Sky Century at Harvard. II: Initial Photometry and Astrometry
S. Laycock, S. Tang, J. Grindlay +3
Digital Access to a Sky Century @ Harvard (DASCH) is a project to digitize the collection of ~500,000 glass photographic plates held at Harvard College Observatory. The collection…
Chandra X-Ray Observatory Observations of the Globular Cluster M71
R. F. Elsner, C. O. Heinke, H. N. Cohn +12
We observed the nearby, low-density globular cluster M71 (NGC 6838) with the Chandra X-ray Observatory to study its faint X-ray populations. Five X-ray sources were found inside th…
Investigating ChaMPlane X-ray sources in the Galactic Bulge with Magellan LDSS2 spectra
Xavier Koenig, Jonathan E. Grindlay, Maureen van den Berg +4
We have carried out optical and X-ray spectral analyses on a sample of 136 candidate optical counterparts of X-ray sources found in five Galactic-bulge fields included in our Chand…
Thermal X-rays from Millisecond Pulsars: Constraining the Fundamental Properties of Neutron Stars
Slavko Bogdanov, Jonathan E. Grindlay, George B. Rybicki
Abridged) We model the X-ray properties of millisecond pulsars (MSPs) by considering hot spot emission from a weakly magnetized rotating neutron star (NS) covered by an optically-t…
An X-ray View of Radio Millisecond Pulsars
Slavko Bogdanov, Jonathan E. Grindlay
In recent years, X-ray observations with Chandra and XMM-Newton have significantly increased our understanding of rotation-powered (radio) millisecond pulsars (MSPs). Deep Chandra…
Chandra ACIS Survey of M33 (ChASeM33): A First Look
Paul P. Plucinsky, Benjamin Williams, Knox S. Long +22
We present an overview of the Chandra ACIS Survey of M33 (ChASeM33): A Deep Survey of the Nearest Face-on Spiral Galaxy. The 1.4 Ms survey covers the galaxy out to $R \approx 18\ar…
Relativistic iron emission lines in neutron star low-mass X-ray binaries as probes of neutron star radii
Edward M. Cackett, Jon M. Miller, Sudip Bhattacharyya +6
Using Suzaku observations of three neutron star low-mass X-ray binaries (Ser X-1, 4U 1820-30 and GX 349+2) we have found broad, asymmetric, relativistic Fe K emission lines in all…
Jets, Blazars and the EBL in the GLAST-EXIST Era
Jonathan E. Grindlay, the EXIST Team
The synergy of GLAST and the proposed EXIST mission as the Black Hole Finder Probe in the Beyond Einstein Program is remarkable. With its full-sky per orbit hard X-ray imaging (3-6…
AGN Variability Surveys: DASCH from BATSS to EXIST
Jonathan E. Grindlay
Active galactic nuclei (AGN) are variable on a wide range of timescales, though relatively few systematic variability surveys have been conducted. Previous broad-band (both spectra…
Comptonization in the X-ray Spectra of Radio Millisecond Pulsars
Slavko Bogdanov, Jonathan E. Grindlay, George B. Rybicki
The majority of X-ray-detected rotation-powered millisecond pulsars (MSPs) appear to exhibit predominantly thermal emission, believed to originate from the heated magnetic polar ca…
Constraints on Neutron Star Properties from X-ray Observations of Millisecond Pulsars
Slavko Bogdanov, George B. Rybicki, Jonathan E. Grindlay
We present a model of thermal X-ray emission from hot spots on the surface of a rotating compact star with an unmagnetized light-element atmosphere. An application to ROSAT, Chandr…
An ultrahigh-speed digitizer for the Harvard College Observatory astronomical plates
R. J. Simcoe, J. E. Grindlay, E. J. Los +5
A machine capable of digitizing two 8 inch by 10 inch (203 mm by 254 mm) glass astrophotographic plates or a single 14 inch by 17 inch (356 mm by 432 mm) plate at a resolution of 1…
CZT in Space Based Hard-X-ray Astronomy
A. Garson, H. Krawczynski, G. Weidenspointner +4
One of the key aspects of a detector material for space-borne hard X-ray and gamma-ray telescopes is the rate of prompt and delayed background events generated inside the material…
Chandra X-ray Sources in the Collapsed-Core Globular Cluster M30 (NGC 7099)
Phyllis M. Lugger, Haldan N. Cohn, Craig O. Heinke +2
We report the detection of six discrete, low-luminosity (Lx < 10^33 erg/s) X-ray sources, located within 12 arcsec of the center of the collapsed-core globular cluster M30 (NGC 709…
Faint X-ray Sources in the Globular Cluster Terzan 5
C. O. Heinke, R. Wijnands, H. N. Cohn +4
We report our analysis of a Chandra X-ray observation of the rich globular cluster Terzan 5, in which we detect 50 sources to a limiting 1.0-6 keV X-ray luminosity of 3*10^{31} erg…
X-rays from Radio Millisecond Pulsars: Comptonized Thermal Radiation
Slavko Bogdanov, Jonathan E. Grindlay, George B. Rybicki
X-ray emission from many rotation-powered millisecond pulsars (MSPs) is observed to be of predominantly thermal nature. In PSR J0437--4715, the nearest MSP known, an additional fai…
Compact X-ray Binaries in and out of Core Collapsed Globulars
Jonathan E. Grindlay
We review new Chandra and HST observations of the core collapsed cluster NGC 6397 as a guide to understanding the compact binary (CB) populations in core collapse globulars. New ca…
A Neutron Star in F-sharp
Jonathan E. Grindlay
In this short introductory commentary on the paper (Hessels et al 2006, Science, 311, 1901) reporting the discovery of the shortest spin period millisecond pulsar (MSP) Ter5-ad in…
Post-Swift Gamma-ray Burst Science and Capabilities Needed to EXIST
Jonathan E. Grindlay
The exhilerating results from Swift in its first year of operations have opened a new era of exploration of the high energy universe. The surge to higher redshifts of the Gamma-ray…
Chandra X-Ray Observations of Nineteen Millisecond Pulsars in the Globular Cluster 47 Tucanae
Slavko Bogdanov, Jonathan E. Grindlay, Craig O. Heinke +3
We present spectral and long-timescale variability analyses of \textit{Chandra} ACIS-S observations of the 19 millisecond pulsars (MSPs) with precisely known positions in the globu…
EXIST: All-Sky Hard X-ray Imaging and Spectral-Temporal Survey for Black Holes
Jonathan E. Grindlay
The Energetic X-ray Imaging Survey Telescope (EXIST) is under study for the proposed Black Hole Finder Probe, one of the three Einstein Probe missions in NASA's proposed Beyond Ein…
Interacting X-ray Binaries in Globular Clusters: 47Tuc vs. NGC 6397
Jonathan E. Grindlay
Our deep Chandra exposures of 47Tuc and moderate exposures of NGC 6397 reveal a wealth of new phenomena for interacting X-ray binaries (IXBs) in globular clusters. In this (late) R…
Short gamma-ray bursts from binary neutron star mergers in globular clusters
Jonathan Grindlay, Simon Portegies Zwart, Stephen McMillan
The first locations of short gamma-ray bursts (GRBs) in elliptical galaxies suggest they are produced by the mergers of double neutron star (DNS) binaries in old stellar population…
A Chandra X-ray observation of the globular cluster Terzan 1
E. M. Cackett, R. Wijnands, C. O. Heinke +6
We present a 19 ks Chandra ACIS-S observation of the globular cluster Terzan 1. Fourteen sources are detected within 1.4 arcmin of the cluster center with 2 of these sources predic…