The Nature of the Bright ULX X-2 in NGC 3921: A Chandra Position and HST Candidate Counterpart
We report on Chandra observations of the bright ultraluminous X-ray (ULX) source in NGC 3921. Previous XMM-Newton observations reported in the literature show the presence of a bright ULX at a 0.5-10 keV luminosity of 2 × 10^40 erg/s. Our Chandra observation finds the source at a lower luminosity of...
| Main Authors: | , , , , , , , , |
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| Format: | Journal Article |
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Institute of Physics Publishing, Inc.
2012
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| Online Access: | http://hdl.handle.net/20.500.11937/24786 |
| _version_ | 1848751526057607168 |
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| author | Jonker, P. Heida, M. Torres, M. Miller-Jones, James Fabian, A. Ratti, E. Miniutti, G. Walton, D. Roberts, T. |
| author_facet | Jonker, P. Heida, M. Torres, M. Miller-Jones, James Fabian, A. Ratti, E. Miniutti, G. Walton, D. Roberts, T. |
| author_sort | Jonker, P. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We report on Chandra observations of the bright ultraluminous X-ray (ULX) source in NGC 3921. Previous XMM-Newton observations reported in the literature show the presence of a bright ULX at a 0.5-10 keV luminosity of 2 × 10^40 erg/s. Our Chandra observation finds the source at a lower luminosity of ˜8 × 10^39 erg/s furthermore, we provide a Chandra position of the ULX accurate to 0.7" at 90% confidence. The X-ray variability makes it unlikely that the high luminosity is caused by several separate X-ray sources. In three epochs of archival Hubble Space Telescope observations, we find a candidate counterpart to the ULX. There is direct evidence for variability between the two epochs of WFPC2 F814W observations with the observation obtained in 2000 showing a brighter source. Furthermore, converting the 1994 F336W and 2000 F300W WFPC2 and the 2010 F336W WFC3 observations to the Johnson U-band filter assuming a spectral type of O7I, we find evidence for a brightening of the U-band light in 2000. Using the higher resolution WFC3 observations, we resolve the candidate counterpart into two sources of similar color. We discuss the nature of the ULX and the probable association with the optical counterpart(s). Finally, we investigate a potential new explanation for some (bright) ULXs as the decaying stages of flares caused by the tidal disruption of a star by a recoiled supermassive black hole. However, we find that there should be at most only one of such systems within z = 0.08. |
| first_indexed | 2025-11-14T07:54:07Z |
| format | Journal Article |
| id | curtin-20.500.11937-24786 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:54:07Z |
| publishDate | 2012 |
| publisher | Institute of Physics Publishing, Inc. |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-247862023-02-22T06:24:24Z The Nature of the Bright ULX X-2 in NGC 3921: A Chandra Position and HST Candidate Counterpart Jonker, P. Heida, M. Torres, M. Miller-Jones, James Fabian, A. Ratti, E. Miniutti, G. Walton, D. Roberts, T. X-rays: binaries binaries: close We report on Chandra observations of the bright ultraluminous X-ray (ULX) source in NGC 3921. Previous XMM-Newton observations reported in the literature show the presence of a bright ULX at a 0.5-10 keV luminosity of 2 × 10^40 erg/s. Our Chandra observation finds the source at a lower luminosity of ˜8 × 10^39 erg/s furthermore, we provide a Chandra position of the ULX accurate to 0.7" at 90% confidence. The X-ray variability makes it unlikely that the high luminosity is caused by several separate X-ray sources. In three epochs of archival Hubble Space Telescope observations, we find a candidate counterpart to the ULX. There is direct evidence for variability between the two epochs of WFPC2 F814W observations with the observation obtained in 2000 showing a brighter source. Furthermore, converting the 1994 F336W and 2000 F300W WFPC2 and the 2010 F336W WFC3 observations to the Johnson U-band filter assuming a spectral type of O7I, we find evidence for a brightening of the U-band light in 2000. Using the higher resolution WFC3 observations, we resolve the candidate counterpart into two sources of similar color. We discuss the nature of the ULX and the probable association with the optical counterpart(s). Finally, we investigate a potential new explanation for some (bright) ULXs as the decaying stages of flares caused by the tidal disruption of a star by a recoiled supermassive black hole. However, we find that there should be at most only one of such systems within z = 0.08. 2012 Journal Article http://hdl.handle.net/20.500.11937/24786 10.1088/0004-637X/758/1/28 Institute of Physics Publishing, Inc. unknown |
| spellingShingle | X-rays: binaries binaries: close Jonker, P. Heida, M. Torres, M. Miller-Jones, James Fabian, A. Ratti, E. Miniutti, G. Walton, D. Roberts, T. The Nature of the Bright ULX X-2 in NGC 3921: A Chandra Position and HST Candidate Counterpart |
| title | The Nature of the Bright ULX X-2 in NGC 3921: A Chandra Position and HST Candidate Counterpart |
| title_full | The Nature of the Bright ULX X-2 in NGC 3921: A Chandra Position and HST Candidate Counterpart |
| title_fullStr | The Nature of the Bright ULX X-2 in NGC 3921: A Chandra Position and HST Candidate Counterpart |
| title_full_unstemmed | The Nature of the Bright ULX X-2 in NGC 3921: A Chandra Position and HST Candidate Counterpart |
| title_short | The Nature of the Bright ULX X-2 in NGC 3921: A Chandra Position and HST Candidate Counterpart |
| title_sort | nature of the bright ulx x-2 in ngc 3921: a chandra position and hst candidate counterpart |
| topic | X-rays: binaries binaries: close |
| url | http://hdl.handle.net/20.500.11937/24786 |