X-RAY SOURCES AND THEIR OPTICAL COUNTERPARTS IN THE GALACTIC GLOBULAR CLUSTER M12 (NGC 6218)

Lu, T -N; Kong, Albert K. H.; Bassa, Cees; Verbunt, Frank; Lewin, Walter H. G.; Anderson, Scott F; Pooley, David

doi:10.1088/0004-637X/705/1/175

Title: X-RAY SOURCES AND THEIR OPTICAL COUNTERPARTS IN THE GALACTIC GLOBULAR CLUSTER M12 (NGC 6218)

Full Record
Other Related Research

Abstract

We study a Chandra X-ray Observatory ACIS-S observation of the Galactic globular cluster M12. With a 26 ks exposure time, we detect six X-ray sources inside the half-mass radius (2.'16) of which two are inside the core radius (0.'72) of the cluster. If we assume that these sources are all associated with globular cluster M12, the luminosity L {sub X} among these sources between 0.3 and 7.0 keV varies roughly from 10{sup 30} to 10{sup 32} erg s{sup -1}. For identification, we also analyzed the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) and Wide Field and Planetary Camera 2 (WFPC2) data and identified the optical counterparts to five X-ray sources inside the HST ACS field of view. According to the X-ray and optical features, we found 2-5 candidate active binaries (ABs) or cataclysmic variables (CVs) and 0-3 background galaxies within the HST ACS field of view. Based on the assumption that the number of X-ray sources scales with the encounter rate and the mass of the globular cluster, we expect two X-ray sources inside M12, and the expectation is consistent with our observational results. Therefore, the existence of identified X-ray sources (possible CVs or ABs) in M12 suggestsmore »« less

Authors:

Lu, T -N; Kong, Albert K. H. ^[1]; Bassa, Cees ^[2]; Verbunt, Frank ^[3]; Lewin, Walter H. G. ^[4]; Anderson, Scott F ^[5]; Pooley, David ^[6]

Institute of Astronomy and Department of Physics, National Tsing Hua University, Taiwan (China)
SRON, Netherlands Institute for Space Research Sorbonnelaan 2, 3584 CA, Utrecht (Netherlands)
Astronomical Institute, Utrecht University, P.O. Box 80000, 3508 TA, Utrecht (Netherlands)
Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)
Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States)
Astronomy Department, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States)

Publication Date:: Sun Nov 01 00:00:00 EDT 2009

OSTI Identifier:: 21378410

Resource Type:: Journal Article

Journal Name:: Astrophysical Journal

Additional Journal Information:: Journal Volume: 705; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/705/1/175; Journal ID: ISSN 0004-637X

Country of Publication:: United States

Language:: English

Subject:: 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CAMERAS; COSMIC X-RAY SOURCES; GALAXIES; LUMINOSITY; MASS; NOVAE; TELESCOPES; BINARY STARS; COSMIC RAY SOURCES; ERUPTIVE VARIABLE STARS; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; STARS; VARIABLE STARS

Citation Formats


                    Lu, T -N, Kong, Albert K. H., Bassa, Cees, Verbunt, Frank, Lewin, Walter H. G., Anderson, Scott F, and Pooley, David. X-RAY SOURCES AND THEIR OPTICAL COUNTERPARTS IN THE GALACTIC GLOBULAR CLUSTER M12 (NGC 6218).  United States: N. p., 2009. 
        Web.  doi:10.1088/0004-637X/705/1/175.

Copy to clipboard


                    Lu, T -N, Kong, Albert K. H., Bassa, Cees, Verbunt, Frank, Lewin, Walter H. G., Anderson, Scott F, & Pooley, David. X-RAY SOURCES AND THEIR OPTICAL COUNTERPARTS IN THE GALACTIC GLOBULAR CLUSTER M12 (NGC 6218).  United States.  https://doi.org/10.1088/0004-637X/705/1/175

Copy to clipboard


                    Lu, T -N, Kong, Albert K. H., Bassa, Cees, Verbunt, Frank, Lewin, Walter H. G., Anderson, Scott F, and Pooley, David. 2009.  
        "X-RAY SOURCES AND THEIR OPTICAL COUNTERPARTS IN THE GALACTIC GLOBULAR CLUSTER M12 (NGC 6218)".  United States.  https://doi.org/10.1088/0004-637X/705/1/175.

Copy to clipboard


                    
@article{osti_21378410,

  title        = {X-RAY SOURCES AND THEIR OPTICAL COUNTERPARTS IN THE GALACTIC GLOBULAR CLUSTER M12 (NGC 6218)},

  author       = {Lu, T -N and Kong, Albert K. H. and Bassa, Cees and Verbunt, Frank and Lewin, Walter H. G. and Anderson, Scott F and Pooley, David},

  abstractNote = {We study a Chandra X-ray Observatory ACIS-S observation of the Galactic globular cluster M12. With a 26 ks exposure time, we detect six X-ray sources inside the half-mass radius (2.'16) of which two are inside the core radius (0.'72) of the cluster. If we assume that these sources are all associated with globular cluster M12, the luminosity L {sub X} among these sources between 0.3 and 7.0 keV varies roughly from 10{sup 30} to 10{sup 32} erg s{sup -1}. For identification, we also analyzed the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) and Wide Field and Planetary Camera 2 (WFPC2) data and identified the optical counterparts to five X-ray sources inside the HST ACS field of view. According to the X-ray and optical features, we found 2-5 candidate active binaries (ABs) or cataclysmic variables (CVs) and 0-3 background galaxies within the HST ACS field of view. Based on the assumption that the number of X-ray sources scales with the encounter rate and the mass of the globular cluster, we expect two X-ray sources inside M12, and the expectation is consistent with our observational results. Therefore, the existence of identified X-ray sources (possible CVs or ABs) in M12 suggests the primordial origin of X-ray sources in globular clusters which is in agreement with previous studies.},

  doi          = {10.1088/0004-637X/705/1/175},

  url          = {https://www.osti.gov/biblio/21378410},
  journal      = {Astrophysical Journal},

  issn         = {0004-637X},

  number       = 1,

  volume       = 705,

  place        = {United States},

  year         = {Sun Nov 01 00:00:00 EDT 2009},

  month        = {Sun Nov 01 00:00:00 EDT 2009}

}

Copy to clipboard

Journal Article:

https://doi.org/10.1088/0004-637X/705/1/175

Other availability

Find in Google Scholar

Search WorldCat to find libraries that may hold this journal

Save / Share:

Export Metadata

Save to My Library

Similar records in OSTI.GOV collections:

IDENTIFICATION OF FAINT CHANDRA X-RAY SOURCES IN THE CORE-COLLAPSED GLOBULAR CLUSTER NGC 6397: EVIDENCE FOR A BIMODAL CATACLYSMIC VARIABLE POPULATION

Journal Article Cohn, Haldan; Lugger, Phyllis; Couch, Sean; ... - Astrophysical Journal

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 H{alpha}, R, and B. Photometry of these images allows us to classify candidate counterparts based on color-magnitude diagram location. In addition to recovering nine previously detected cataclysmic variables (CVs), we have identified six additional faint CV candidates, a total of 42 active binaries (ABs), two millisecond pulsars, one candidate active galactic nucleus, and one candidate interacting galaxy pair. Of the 79more »« less
https://doi.org/10.1088/0004-637X/722/1/20
A CHANDRA STUDY OF THE GALACTIC GLOBULAR CLUSTER OMEGA CENTAURI

Journal Article Haggard, Daryl; Cool, Adrienne - Astrophysical Journal

We analyze a {approx}70 ks Chandra Advanced CCD Imaging Spectrometer exposure of the globular cluster {omega} Cen (NGC 5139). The {approx}17' x 17' field of view fully encompasses three core radii and almost twice the half-mass radius. We detect 180 sources to a limiting flux of {approx}4.3 x 10{sup -16} erg cm{sup -2} s{sup -1} (L{sub x} = 1.2 x 10{sup 30} erg s{sup -1} at 4.9 kpc). After accounting for the number of active galactic nuclei and possible foreground stars, we estimate that 45-70 of the sources are cluster members. Four of the X-ray sources have previously been identifiedmore »« less
https://doi.org/10.1088/0004-637X/697/1/224; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
CHANDRA AND HST STUDIES OF THE X-RAY SOURCES IN GALACTIC GLOBULAR CLUSTER M92

Journal Article Lu, Ting-Ni; Kong, Albert; Verbunt, Frank; ... - Astrophysical Journal

We present the analysis of two observations of M92 taken with the Chandra X-Ray Observatory. We combined the two data sets with a total exposure of {approx}52 ks. With the combined observation, we detected 10 X-ray sources inside the half-mass radius (1.'02), five of which are inside the core radius (0.'26) of M92. The luminosities of the 10 sources are roughly within the range of 10{sup 30}-10{sup 32} erg s{sup -1} assuming cluster memberships. The background estimation suggests 7-8 cluster members and 2-3 background galaxies in M92. We identified the 10 sources by using Hubble Space Telescope Advanced Camera formore »« less
https://doi.org/10.1088/0004-637X/736/2/158
HST/ACS IMAGING OF OMEGA CENTAURI: OPTICAL COUNTERPARTS OF CHANDRA X-RAY SOURCES

Journal Article Cool, Adrienne; Arias, Tersi; Brochmann, Michelle; ... - Astrophysical Journal

We present results of a search for optical counterparts of X-ray sources in and toward the globular cluster Omega Centauri (NGC 5139) using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The ACS data consist of a mosaic of Wide Field Channel images obtained using F625W, F435W, and F658N filters; with nine pointings we cover the central {approx}10' Multiplication-Sign 10' of the cluster and encompass 109 known Chandra sources. We find promising optical counterparts for 59 of the sources, {approx}40 of which are likely to be associated with the cluster. These include 27 candidate cataclysmic variables (CVs),more »« less
https://doi.org/10.1088/0004-637X/763/2/126
Lithium abundances in globular cluster giants: NGC 6218 (M12) and NGC 5904 (M5)

Journal Article D'Orazi, Valentina; Angelou, George; Lattanzio, John; ... - Astrophysical Journal

Convergent lines of evidence suggest that globular clusters host multiple stellar populations. It appears that they experience at least two episodes of star formation whereby a fraction of first-generation stars contribute astrated ejecta to form the second generation(s). To identify the polluting progenitors, we require distinguishing chemical signatures such as that provided by lithium. Theoretical models predict that lithium can be synthesized in AGB stars, whereas no net Li production is expected from other candidates. It has been shown that in order to reproduce the abundance pattern found in M4, Li production must occur within the polluters, favoring the AGBmore »« less
https://doi.org/10.1088/0004-637X/791/1/39

Similar Records