Review of Discrete X-Ray Sources in the Small Magellanic Cloud: Summary of the ASCA Results and Implication on the Recent Star Forming Activity
arXiv:astro-ph/0302163 · doi:10.1093/pasj/55.1.161
Abstract
We made 22 observations on the Small Magellanic Cloud (SMC) and covered full regions by the end of the ASCA mission. We detected 106 discrete sources with a criterion of S/N > 5 and performed systematic analyses on all of the sources. We determined the source positions with an ~40'' error radius (90% confidence) for sources detected in the central 20' radius of the GIS. We detected coherent pulsations from 17 sources. Among them, eight were newly discovered during this study. We classified most of these pulsars as X-ray binary pulsars (XBPs) based on their properties, such as the flux variability and the existence of an optical counterpart. We detected X-ray emission from eight supernova remnants (SNRs). Among them, five SNRs showed emission lines in their spectra, hence we regarded the five as thermal SNRs. We found that XBPs and thermal SNRs in the SMC can be clearly separated by their spectral hardness ratio. Applying this empirical law to faint (thus unclassified) sources, we found 19 XBP candidates and four thermal SNR candidates. We also found several tens of candidates for active galactic nuclei, both from the hardness ratio and the logN--logS relation of extragalactic sources. Based on these ASCA results and further information from other sattelites, we compiled comprehensive catalogues of discrete X-ray sources in the Small Magellanic Cloud. Using the catalogues, we derived the spatial distributions of XBPs and SNRs. XBPs and SNRs were found to be concentrated in the main body and eastern wing, which resembles the distribution of young stars with ages of ~2e7yr. By comparing the source populations in the SMC and our Galaxy, we suggest that the star-forming rate (per unit mass) in the SMC was much higher than the Galaxy 1e7yr ago. We also discuss the recent change of the star-forming rate in the SMC.
arXiv comment61 pages, 19 figures, to be published in PASJ. Also available at http://www-cr.scphys.kyoto-u.ac.jp/member/jun/job/ (with high-resolution images)
References in corpus (41)
- Observations of Accreting Pulsars
- Log N - Log S Relations and Spectral Properties of Sources from the ASCA Large Sky Survey --- their Implications for the Origin of the Cosmic X-ray Background (CXB)
- Discovery of two new persistent Be/X-ray pulsar systems
- Quasi-Periodic Occultation by a Precessing Accretion Disk and Other Variabilities of SMC X-1
- Updated Information on the Local Group
- Supernova Remnants in the Magellanic Clouds III: An X-ray Atlas of LMC Supernova Remnants
- Nature of the Soft Spectral Component in the X-ray Pulsars SMC X-1 and LMC X-4
- Discovery of a Transient X-Ray Pulsar, AX J1841.0-0536, in the Scutum Arm Region with ASCA
- Discovery of a Possible Anomalous X-ray Pulsar in the Small Magellanic Cloud
- ROSAT HRI catalogue of X-ray sources in the SMC region
- A Study of the Populations of X-ray Sources in the Small Magellanic Cloud with ASCA
- Magellanic Cloud X-ray Sources: III. Completion of a ROSAT Survey
- Discovery of a Hard X-Ray Source, SAX J0635+0533, in the Error Box of the Gamma-Ray Source 2EG 0635+0521
- The Discovery of an Outburst and Pulsed X-ray Flux from SMC X-2 from RXTE Observations
- ASCA Observation of the New Transient X-ray Pulsar XTE J0111.2-7317 in the Small Magellanic Cloud
- BeppoSAX and Chandra Observations of SAXJ0103.2-7209=2E0101.5-7225: a new Persistent 345s X-ray Pulsar in the SMC
- Discovery of the Slowest X-Ray Pulsar in the SMC, AX J0049.5-7323, with ASCA
- Detection of 33.8 ms X-ray pulsations in SAX J0635+0533
- 4U2206+54 - an Unusual High Mass X-ray Binary with a 9.6 Day Orbital Period but No Strong Pulsations
- Broad-Band X-Ray Study of a Transient Pulsar RX J0059.2-7138
- OGLE observations of four X-ray binary pulsars in the SMC
- Discovery of Pulsed X-ray Emission from the SMC Transient RX J0117.6-7330
- The discovery of 8.9s pulsations from the variable X-ray source 2E0050.1-7247 in the small Magellanic cloud
- Catalogue of candidate emission-line objects in the Small Magellanic Cloud
- Observations of the unusual counterpart to the X-ray pulsar AX J0051-733
- Discovery of a Slow X-Ray Pulsator, AX J1740.1-2847, in the Galactic Center Region
- The SMC X-ray transient XTE J0111.2-7317 : a Be/X-ray binary in a SNR?
- Discovery of 16.6 and 25.5 s Pulsations from the Small Magellanic Cloud
- Discovery of 172-s Pulsations from a Be/X-ray Binary Candidate AX J0051.6-7311 in the SMC with ASCA
- Discovery of pulsations from the Be/X-ray binary RX J0101.3-7211 in the SMC by XMM-Newton
- ASCA Identification of SMC X-2 with the 2.37-s Pulsar Discovered by RXTE
- Discovery of a 1247 s pulsar in the Be X-ray binary SAX J2239.3+6116
- ASCA Discovery of a Be X-Ray Pulsar in the SMC: AX J0051-733
- Multiwaveband studies of the hard ROSAT SMC transient 1WGA J0053.8-7226: a new X-ray pulsar
- Centrally Peaked X-Ray Supernova Remnants in the Small Magellanic Cloud Studied with ASCA and ROSAT
- Discovery of a new Transient X-ray Pulsar in the Small Magellanic Cloud
- Discovery of an X-Ray Pulsar in the SMC: AX J0058-7203
- Discovery of a 9-s X-Ray Pulsar, AX J0049-732, in the Small Magellanic Cloud
- The optical counterpart of the supersoft Small Magellanic Cloud transient pulsar RX~J0059.2-7138
- Discovery of 101-s Pulsations from AX J0057.4-7325 in the SMC with ASCA
- A 168-s X-Ray Pulsar in the SMC Observed with ASCA
Cited by in corpus (45)
- Be/X-ray binaries
- X-ray emission from star-forming galaxies - I. High-mass X-ray binaries
- Origin of the Soft Excess in X-ray Pulsars
- High-Mass X-ray binaries in the Small Magellanic Cloud
- The XMM-Newton survey of the Small Magellanic Cloud: The X-ray point-source catalogue
- X-ray observations of Be/X-ray binaries in the SMC
- A Long Look at the Be/X-Ray Binaries of the Small Magellanic Cloud
- Spectral distribution of Be/X-ray binaries in the Small Magellanic Cloud
- High mass X-ray binaries in the SMC: the luminosity function
- The XMM-Newton survey of the Small Magellanic Cloud
- XMM-Newton observations of the Small Magellanic Cloud: Be/X-ray binary pulsars active between October 2006 and June 2007
- New XMM-Newton observations of SNRs in the SMC
- X-ray Pulsars in the Small Magellanic Cloud
- A Comprehensive Library of X-ray Pulsars in the Small Magellanic Cloud: Time Evolution of their Luminosities and Spin Periods
- Optical spectroscopy of 20 Be/X-ray Binaries in the Small Magellanic Cloud
- Exploring the Small Magellanic Cloud to the Faintest X-ray Fluxes: Source Catalog, Timing and Spectral Analysis
- XMM-Newton observation of the Be/neutron star system RX J0146.9+6121: a soft X-ray excess in a low luminosity accreting pulsar
- Deep Chandra survey of the Small Magellanic Cloud. III. Formation efficiency of High-Mass X-ray binaries
- The Chandra survey of the SMC "Bar": II. Optical counterparts of X-ray sources
- Discovery of 1323 s pulsations from RX J0103.6-7201: the longest period X-ray pulsar in the SMC
- Three new X-ray pulsars detected in the Small Magellanic Cloud and the positions of two other known pulsars determined
- Deep XMM-Newton observation of a northern LMC field: I. Selected X-ray sources
- Could SXP 1062 be an Accreting Magnetar?
- XMM-Newton observation of the persistent Be/NS X-ray binary pulsar RX J1037.5-5647 in a low luminosity state
- The Ages of High Mass X-ray Binaries in NGC 2403 and NGC 300
- Chandra and XMM-Newton discovery of the transient X-ray pulsar in the nearby spiral galaxy NGC2403
- Two long-period X-ray pulsars detected in the SMC field around XTE J0055-727
- Periodic Optical Outbursts from the Be/Neutron Star Binary AX J0049.4-7323
- XMM-Newton observations of the Small Magellanic Cloud: XMMU J004814.1-731003, a 25.55 s Be/X-ray binary pulsar
- Long-term evolution of the neutron-star spin period of SXP 1062
- eROSITA calibration and performance verification phase: High-mass X-ray binaries in the Magellanic Clouds
- An Investigation of Be/X-ray Pulsars with OGLE-III Data
- Radiative Column and Light Curve of X-Ray Binary Pulsars
- Identifying New X-ray Binary Candidates in M31 using Random Forest Classification
- The Magellanic Bridge: evidence for a population of X-ray binaries
- Detection of a Rare Supersoft Outburst Event during a Suzaku Observation of 1E0102.2-7219
- A Discovery of a Peculiar Pulsar in the Small Magellanic Cloud
- A multi-observatory database of X-ray pulsars in the Magellanic Clouds
- Contrasting behaviour from two Be/X-ray binary pulsars: insights into differing neutron star accretion modes
- Detection of a 522 s Pulsation from the Transient X-ray Source Suzaku J0102.8--7204 (SXP 523) in the Small Magellanic Cloud
- The binary period and outburst behaviour of the SMC X-ray binary pulsar system SXP504
- Timing and spectral studies of the transient X-ray pulsar EXO 053109-6609.2 with ASCA and Beppo-SAX
- A Striking Confluence Between Theory and Observations of High-Mass X-ray Binary Pulsars
- Probing the nature of AX J0043-737: Not an 87 ms pulsar in the SMC
- Super-critical accretion of BeXRB SXP 15.3