Monitoring the X-Ray Variability of Bright X-Ray Sources in M33
We present a new five-epoch Chandra X-ray Observatory monitoring survey of the nearby spiral galaxy M33 which probes X-ray variability with time sampling between two weeks and four months. We characterize the X-ray variability of 55 bright point sources outside of the nucleus, many of which are expe...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/ad151a |
| _version_ | 1797347660891422720 |
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| author | Rebecca Kyer Shelby Albrecht Benjamin F. Williams Kyros Hinton Breanna Binder Margaret Lazzarini Kristen Garofali Bret Lehmer Michael Eracleous Paul P. Plucinsky Vallia Antoniou |
| author_facet | Rebecca Kyer Shelby Albrecht Benjamin F. Williams Kyros Hinton Breanna Binder Margaret Lazzarini Kristen Garofali Bret Lehmer Michael Eracleous Paul P. Plucinsky Vallia Antoniou |
| author_sort | Rebecca Kyer |
| collection | DOAJ |
| description | We present a new five-epoch Chandra X-ray Observatory monitoring survey of the nearby spiral galaxy M33 which probes X-ray variability with time sampling between two weeks and four months. We characterize the X-ray variability of 55 bright point sources outside of the nucleus, many of which are expected to be high-mass X-ray binaries (HMXBs). We detect eight new candidate transients not detected in previous X-ray catalogs of M33 and discuss their possible nature. The final catalog includes 26 known HMXB candidates identified in the literature. We extend the baseline of the X-ray light curves up to 21 yr by including archival X-ray observations of these sources. We compare the detection and nondetection epochs of the sources to suites of simulated source duty cycles and infer that most of our detected sources have duty cycles >30%. We find only four sources whose detection patterns are consistent with having duty cycles below 30%. This large fraction of sources with high duty cycles is unexpected for a population of HMXBs; thus more frequent X-ray monitoring will likely reveal many more low duty cycle HMXBs in M33. |
| first_indexed | 2024-03-08T11:51:01Z |
| format | Article |
| id | doaj.art-0dd643c4597242e39a236de5ecdcd228 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-08T11:51:01Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-0dd643c4597242e39a236de5ecdcd2282024-01-24T09:23:44ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-01961216810.3847/1538-4357/ad151aMonitoring the X-Ray Variability of Bright X-Ray Sources in M33Rebecca Kyer0https://orcid.org/0009-0006-2411-5162Shelby Albrecht1Benjamin F. Williams2https://orcid.org/0000-0002-7502-0597Kyros Hinton3https://orcid.org/0000-0002-0206-1208Breanna Binder4https://orcid.org/0000-0002-4955-0471Margaret Lazzarini5https://orcid.org/0000-0003-3252-352XKristen Garofali6https://orcid.org/0000-0002-9202-8689Bret Lehmer7https://orcid.org/0000-0003-2192-3296Michael Eracleous8https://orcid.org/0000-0002-3719-940XPaul P. Plucinsky9https://orcid.org/0000-0003-1415-5823Vallia Antoniou10https://orcid.org/0000-0001-7539-1593Department of Physics and Astronomy, Michigan State University , 567 Wilson Road, East Lansing, MI 48824, USA; University of Washington Astronomy Department , Box 351580, Seattle, WA 98195, USAUniversity of Washington Astronomy Department , Box 351580, Seattle, WA 98195, USAUniversity of Washington Astronomy Department , Box 351580, Seattle, WA 98195, USAUniversity of Washington Astronomy Department , Box 351580, Seattle, WA 98195, USADepartment of Physics & Astronomy, California State Polytechnic University , 3801 W. Temple Avenue, Pomona, CA 91768, USADepartment of Physics and Astronomy, California State University Los Angeles , Los Angeles, CA 90032, USA; Division of Physics, Mathematics and Astronomy, California Institute of Technology , 1200 E California Boulevard, Pasadena, CA 91125, USANASA Goddard Space Flight Center , Code 662, Greenbelt, MD 20771, USADepartment of Physics, University of Arkansas , 226 Physics Building, 825 West Dickson Street, Fayetteville, AR 72701, USADepartment of Astronomy & Astrophysics and Institute for Gravitation and the Cosmos, The Pennsylvania State University , 525 Davey Lab, University Park, PA 16802, USACenter for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USACenter for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA; Department of Physics & Astronomy, Texas Tech University , Lubbock, TX 79409, USAWe present a new five-epoch Chandra X-ray Observatory monitoring survey of the nearby spiral galaxy M33 which probes X-ray variability with time sampling between two weeks and four months. We characterize the X-ray variability of 55 bright point sources outside of the nucleus, many of which are expected to be high-mass X-ray binaries (HMXBs). We detect eight new candidate transients not detected in previous X-ray catalogs of M33 and discuss their possible nature. The final catalog includes 26 known HMXB candidates identified in the literature. We extend the baseline of the X-ray light curves up to 21 yr by including archival X-ray observations of these sources. We compare the detection and nondetection epochs of the sources to suites of simulated source duty cycles and infer that most of our detected sources have duty cycles >30%. We find only four sources whose detection patterns are consistent with having duty cycles below 30%. This large fraction of sources with high duty cycles is unexpected for a population of HMXBs; thus more frequent X-ray monitoring will likely reveal many more low duty cycle HMXBs in M33.https://doi.org/10.3847/1538-4357/ad151aX-ray point sourcesX-ray binary starsTriangulum GalaxyX-ray transient sources |
| spellingShingle | Rebecca Kyer Shelby Albrecht Benjamin F. Williams Kyros Hinton Breanna Binder Margaret Lazzarini Kristen Garofali Bret Lehmer Michael Eracleous Paul P. Plucinsky Vallia Antoniou Monitoring the X-Ray Variability of Bright X-Ray Sources in M33 The Astrophysical Journal X-ray point sources X-ray binary stars Triangulum Galaxy X-ray transient sources |
| title | Monitoring the X-Ray Variability of Bright X-Ray Sources in M33 |
| title_full | Monitoring the X-Ray Variability of Bright X-Ray Sources in M33 |
| title_fullStr | Monitoring the X-Ray Variability of Bright X-Ray Sources in M33 |
| title_full_unstemmed | Monitoring the X-Ray Variability of Bright X-Ray Sources in M33 |
| title_short | Monitoring the X-Ray Variability of Bright X-Ray Sources in M33 |
| title_sort | monitoring the x ray variability of bright x ray sources in m33 |
| topic | X-ray point sources X-ray binary stars Triangulum Galaxy X-ray transient sources |
| url | https://doi.org/10.3847/1538-4357/ad151a |
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