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Related papers: High Resolution X-ray Imaging of a Globular Cluste…

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Chandra observations of globular clusters provide insight into the formation, evolution, and X-ray emission mechanisms of X-ray binary populations. Our recent (2002) deep observations of 47 Tuc allow detailed study of its populations of…

We combined Chandra ACIS observations of the globular cluster 47 Tucanae (hereafter, 47 Tuc) from 2000, 2002, and 2014-15 to create a deeper X-ray source list, and study some of the faint radio millisecond pulsars (MSPs) present in this…

High Energy Astrophysical Phenomena · Physics 2017-10-04 Souradeep Bhattacharya , Craig O. Heinke , Andrey I. Chugunov , Paulo C. C. Freire , Alessandro Ridolfi , Slavko Bogdanov

We have detected 300 X-ray sources within the half-mass radius (2.79') of the globular cluster 47 Tucanae in a deep (281 ks) Chandra exposure. We perform photometry and simple spectral fitting for our detected sources, and construct…

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 the cluster core radius, including the known eclipsing binary…

We present results from our 830 ksec observation of the globular cluster 47 Tucanae with the Chandra X-ray Observatory's High Resolution Camera-S. We limit our analysis here to the 19 previously known, localized millisecond pulsars (MSPs)…

Astrophysics · Physics 2011-02-11 P. B. Cameron , R. E. Rutledge , F. Camilo , L. Bildsten , S. M. Ransom , S. R. Kulkarni

We summarize the x-ray properties of the complete samples of millisecond pulsars (MSPs) detected in our Chandra observations of the globular clusters 47 Tuc and NGC 6397. The 47 Tuc MSPs are predominantly soft sources suggestive of thermal…

Astrophysics · Physics 2007-05-23 J. E. Grindlay , C. O. Heinke , P. D. Edmonds , F. Camilo

Our Chandra X-ray observation of the globular cluster 47 Tuc clearly detected most of the 16 MSPs with precise radio positions, and indicates probable X-ray emission from the remainder. The MSPs are soft (BB kT 0.2-0.3 keV) and faint (Lx…

Astrophysics · Physics 2007-05-23 C. O. Heinke , J. E. Grindlay , P. D. Edmonds , F. Camilo

We report results of the Chandra deep imaging observation of the closest post-core collapse globular cluster, NGC 6397. Some 25 sources are detected within 2 arcmin of the cluster center of which about 20 are likely cluster members with L_x…

Astrophysics · Physics 2009-11-07 J. E. Grindlay , C. O. Heinke , P. D. Edmonds , S. S. Murray , A. M. Cool

The high resolution X-ray imaging and broad-band moderate resolution spectra enabled by the ACIS cameras on the Chandra X-ray Observatory have opened a new window in our study of millisecond pulsars (MSPs). Given the large excess of MSPs in…

Astrophysics · Physics 2007-05-23 Jonathan E. Grindlay

We present an analysis of 745.6 ks of archival Chandra X-ray Observatory Advanced CCD Imaging Spectrometer data accumulated between 2000 and 2016 of the millisecond pulsar (MSP) population in the rich Galactic globular cluster Terzan 5.…

High Energy Astrophysical Phenomena · Physics 2021-05-19 Slavko Bogdanov , Arash Bahramian , Craig O. Heinke , Scott M. Ransom

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) Review, updated since the conference, I summarize recent and…

Astrophysics · Physics 2009-11-13 Jonathan E. Grindlay

We report our analysis of a Chandra X-ray observation of the rich globular cluster M80, in which we detect some 19 sources to a limiting 0.5-2.5 keV X-ray luminosity of 7*10^30 ergs/s within the half-mass radius. X-ray spectra indicate that…

Globular clusters with their large populations of millisecond pulsars (MSPs) are believed to be potential emitters of high-energy gamma-ray emission. Our goal is to constrain the millisecond pulsar populations in globular clusters from…

Astrophysics of Galaxies · Physics 2015-05-18 The Fermi LAT collaboration

Using the Hubble Ultraviolet Globular Cluster Survey (HUGS) and additional HST archival data, we have carried out a search for optical counterparts to the low-luminosity Chandra X-ray sources in the globular cluster M4 (NGC 6121). We have…

High Energy Astrophysical Phenomena · Physics 2023-06-28 Phyllis M. Lugger , Haldan N. Cohn , Craig O. Heinke , Jiaqi Zhao , Yue Zhao , Jay Anderson

Using archival {\it Chandra} observations with a total exposure of 510 ks, we present an updated catalog of point sources for Globular Cluster 47 Tucanae. Our study covers an area of $\sim 176.7$ arcmin$^{2}$ (i.e., with…

High Energy Astrophysical Phenomena · Physics 2019-05-15 Zhongqun Cheng , Zhiyuan Li , Xiangdong Li , Xiaojie Xu , Taotao Fang

We report Chandra observations of the complete sample of millisecond pulsars (MSPs) with precise radio positions in the globular clusters 47Tuc (NGC104) and NGC6397. The 47Tuc MSPs are predominantly soft sources suggestive of thermal…

Astrophysics · Physics 2009-11-07 J. E. Grindlay , F. Camilo , C. O. Heinke , P. D. Edmonds , H. Cohn , P. Lugger

Highly sensitive and precise X-ray imaging from Chandra, combined with the superb spatial resolution of HST optical images, dramatically enhances our empirical understanding of compact binaries such as cataclysmic variables and low mass…

Solar and Stellar Astrophysics · Physics 2015-05-20 Bruce Margon , B. Beck-Winchatz , L. Homer , D. Pooley , C. G. Bassa , S. F. Anderson , W. H. G. Lewin , F. Verbunt , A. K. H. Kong , R. M. Plotkin

We have monitored a sample of 27 nearby globular clusters in the hard X-ray band (20-120 keV) for approximately 1400 days using the BATSE instrument on board the Compton Gamma-Ray Observatory. Globular clusters may contain a large number of…

Astrophysics · Physics 2009-10-28 E. Ford , P. Kaaret , B. A. Harmon , M. Tavani , S. N. Zhang

Globular clusters are known to harbour a significant population of neutron star X-ray binaries that could be responsible for delaying the inevitable core collapse of these dense clusters. As a result, their progeny, namely millisecond…

High Energy Astrophysical Phenomena · Physics 2010-01-13 N. A. Webb , J. Knödlseder

We have obtained deep multifrequency radio observations of seven globular clusters using the Very Large Array and the Australia Telescope Compact Array. Five of these, NGC 6440, NGC 6539, NGC 6544, NGC 6624 and Terzan 5 had previously been…

Astrophysics · Physics 2009-10-31 A. S. Fruchter , W. M. Goss
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