- ID:
- ivo://CDS.VizieR/J/ApJ/644/829
- Title:
- Chandra normal galaxies at intermediate redshift
- Short Name:
- J/ApJ/644/829
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have investigated 136 Chandra extragalactic sources, including 93 galaxies with narrow emission lines (NELGs) and 43 with only absorption lines (ALGs). Based on fX/fO, LX, X-ray spectral hardness, and optical emission-line diagnostics, we have conservatively classified 36 normal galaxies and 71 AGNs. Their redshift ranges from 0.01 to 1.2, with normal galaxies in the range z=0.01-0.3. Our normal galaxies appear to share characteristics with local galaxies, as expected from the X-ray binary populations and the hot interstellar matter (ISM). In conjunction with normal galaxies found in other surveys, we found no statistically significant evolution in LX/LB, within the limited z range (<~0.1).
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/418/509
- Title:
- Chandra observation of M67
- Short Name:
- J/A+A/418/509
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a 47-ks Chandra/ACIS observation of the old open cluster M67. We detected 25 proper-motion cluster members (including ten new sources) and 12 sources (all new) that we suspect to be members from their locations close to the main sequence (1<B-V<1.7). Of the detected members, 23 are binaries.
- ID:
- ivo://CDS.VizieR/J/PASJ/57/135
- Title:
- Chandra observation of NGC 2146
- Short Name:
- J/PASJ/57/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present six monitoring observations of the starburst galaxy NGC 2146 using the Chandra X-ray Observatory. We detected 67 point sources in the field of view of the ACIS-S detector. Six of these sources were Ultra-Luminous X-ray Sources, the brightest of which had a luminosity of 5x10^39^erg/s. One of them, with a luminosity of ~1x10^39^erg/s, is coincident with the dynamical center location, which may be a low-luminosity active galactic nucleus. We have produced a table where the positions and main characteristics of the detected sources are reported. A comparison between the positions of the X-ray sources and those detected in NIR or radio indicates no definite counterpart. We have derived a logN-logS relation and a luminosity function. The luminosity function has a slope of 0.71 above a detection limit, which is similar to those found in other starburst galaxies. Diffuse emissions were detected in both soft (0.5-2.0keV) and hard (2.0-10.0keV) energy bands. The spectra of the diffuse component were fitted with two (hard and soft) components. The hard power-law component, with a luminosity of ~4x10^39^erg/s, is likely to have originated by unresolved point sources.
- ID:
- ivo://CDS.VizieR/J/AJ/132/1372
- Title:
- Chandra observation of NGC 6822
- Short Name:
- J/AJ/132/1372
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Chandra observed the nearby dwarf galaxy NGC 6822. There are 70 sources in the Chandra field, two of which are fairly extended and likely background clusters of galaxies. A third source was resolved by Chandra that has the same size and position as a known supernova remnant. The suspected variability detected from this source in previous missions is shown to be in error. The majority of the remaining 67 sources are consistent with background sources. Of the 61 sources detected above a completeness limit of 10 events, we estimate that 9+/-4+/-8 are associated with the galaxy, including both systematic and statistical errors. We compare the X-ray positions of all sources with various catalogs and Hubble Space Telescope data and offer tentative identifications for several. Based on the mass and star formation rate of NGC 6822, we expect only about 10 sources, mostly high-mass systems.
2375. Chandra Observations
- ID:
- ivo://nasa.heasarc/chanmaster
- Title:
- Chandra Observations
- Short Name:
- Chandra
- Date:
- 09 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table contains all of the observations made by the Chandra X-Ray Observatory (CXO, formerly known as the Advanced X-ray Astrophysics Facility or AXAF) as part of the Performance Verification and Calibration (PVC) phase and also contains all of the subsequent Cycles' Guaranteed Time Observers (GTO) and General Observer (GO) targets, and any Director's Discretionary Time (DDT) targets that have been observed. It also includes scheduled and as-yet-not-scheduled targets. The HEASARC updates this database table on a twice-weekly basis by querying the database table at the Chandra X-Ray Center (CXC) website, as discussed in the Provenance section. For observations whose status is 'archived', data products can be retrieved from the HEASARC's mirror of the CXC's Chandra Data Archive (CDA). The CXC should be acknowledged as the source of Chandra data. The PVC phase was during the first few months of the CXO mission; some of the calibration observations that are for monitoring purposes will be performed in later mission cycles. All calibration data (entries with Type = CAL in this database) are placed immediately into the CXO public data archive at the Chandra X-Ray Observatory Center (CXC); please see the Web page at <a href="http://asc.harvard.edu/">http://asc.harvard.edu/</a> for more information on the CXC data archive). GTO observations during Cycle 1 or any subsequent Cycle will probably occupy 100% of months 3-4, 30% of months 5-22, and 15% of the available time for the remainder of the mission. Guaranteed Time Observers will have the same proprietary data rights as General Observers (i.e., their data will be placed in the public CXC archive 12 months after they have received the data in usable form). For detailed information on the Chandra Observatory and datasets see: <pre> <a href="http://cxc.harvard.edu/">http://cxc.harvard.edu/</a> for general Chandra information <a href="http://cxc.harvard.edu/cda/">http://cxc.harvard.edu/cda/</a> for the Chandra Data Archive <a href="http://cxc.harvard.edu/cal/">http://cxc.harvard.edu/cal/</a> for calibration information <a href="http://cxc.harvard.edu/caldb/">http://cxc.harvard.edu/caldb/</a> for the calibration database <a href="http://cxc.harvard.edu/ciao/">http://cxc.harvard.edu/ciao/</a> for data analysis <a href="http://cxc.harvard.edu/ciao/download/">http://cxc.harvard.edu/ciao/download/</a> for analysis software <a href="http://cxc.harvard.edu/ciao/threads/">http://cxc.harvard.edu/ciao/threads/</a> for analysis threads <a href="http://cda.harvard.edu/chaser/">http://cda.harvard.edu/chaser/</a> for WebChaSeR </pre> The HEASARC updates this database table on a twice-weekly basis based on information obtained from the Chandra Data Archive at the CXC website. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/ApJ/777/7
- Title:
- Chandra observations of 8 bulgeless disk galaxies
- Short Name:
- J/ApJ/777/7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used Chandra observations of eight bulgeless disk galaxies to identify new ultraluminous X-ray source (ULX) candidates, study their high-mass X-ray binary (HMXB) population, and search for low-luminosity active galactic nuclei (AGNs). We report the discovery of 16 new ULX candidates in our sample of galaxies. Eight of these are found in the star forming galaxy NGC 337, none of which are expected to be background contaminants. The HMXB luminosity function of NGC 337 implies a star formation rate (SFR) of 6.8_-3.5_^+4.4^M_{sun}/yr, consistent at 1.5{sigma} with a recent state of the art SFR determination. We also report the discovery of a bright ULX candidate (X-1) in ESO 501-23. X-1's spectrum is well fit by an absorbed power law with {Gamma}=1.18_-0.11_^+0.19^ and N_H_=1.13_-1.13_^+7.07^/cm2, implying a 0.3-8keV flux of 1.08_-0.07_^+0.05^x10^-12^erg/s/cm2. Its X-ray luminosity (L_X_) is poorly constrained due to uncertainties in the host galaxy's distance, but we argue that its spectrum implies L_X_>10^40^erg/s. An optical counterpart to this object may be present in an Hubble Space Telescope image. We also identify ULX candidates in IC 1291, PGC 3853, NGC 5964, and NGC 2805. We find no evidence of nuclear activity in the galaxies in our sample, placing a flux upper limit of 4x10^-15^erg/s/cm2 on putative AGN. Additionally, the Type II-P supernova SN 2011DQ in NGC 337, which exploded two months before our X-ray observation, is undetected.
- ID:
- ivo://CDS.VizieR/J/AJ/137/3210
- Title:
- Chandra observations of h Persei
- Short Name:
- J/AJ/137/3210
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe Chandra/ACIS-I observations of the massive ~13-14Myr-old cluster, h Persei, part of the famous Double Cluster (h and {chi} Per) in Perseus. Combining the list of Chandra-detected sources with new optical/IR photometry and optical spectroscopy reveals ~165 X-ray bright stars with V<~23. Roughly 142 have optical magnitudes and colors consistent with cluster membership.
- ID:
- ivo://CDS.VizieR/J/ApJ/836/50
- Title:
- Chandra observations of IC 10
- Short Name:
- J/ApJ/836/50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have monitored the Cassiopeia dwarf galaxy (IC 10) in a series of 10 Chandra ACIS-S observations to capture its variable and transient X-ray source population, which is expected to be dominated by High Mass X-ray Binaries (HMXBs). We present a sample of 21 X-ray sources that are variable between observations at the 3{sigma} level, from a catalog of 110 unique point sources. We find four transients (flux variability ratio greater than 10) and a further eight objects with ratios >5. The observations span the years 2003-2010 and reach a limiting luminosity of >10^35^erg/s, providing sensitivity to X-ray binaries in IC 10 as well as flare stars in the foreground Milky Way. The nature of the variable sources is investigated from light curves, X-ray spectra, energy quantiles, and optical counterparts. The purpose of this study is to discover the composition of the X-ray binary population in a young starburst environment. IC 10 provides a sharp contrast in stellar population age (<10My) when compared to the Magellanic Clouds (40-200My) where most of the known HMXBs reside. We find 10 strong HMXB candidates, 2 probable background Active Galactic Nuclei, 4 foreground flare-stars or active binaries, and 5 not yet classifiable sources. Complete classification of the sample requires optical spectroscopy for radial velocity analysis and deeper X-ray observations to obtain higher S/N spectra and search for pulsations. A catalog and supporting data set are provided.
- ID:
- ivo://CDS.VizieR/J/ApJ/816/38
- Title:
- Chandra observations of 8 INTEGRAL sources
- Short Name:
- J/ApJ/816/38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on 0.3-10keV observations with the Chandra X-ray Observatory of eight hard X-ray sources discovered within 8{deg} of the Galactic plane by the International Gamma-ray Astrophysics Laboratory (INTEGRAL) satellite. The short (~5ks) Chandra observations of the IGR source fields have yielded very likely identifications of X-ray counterparts for three of the IGR sources: IGRJ14091-6108, IGRJ18088-2741, and IGRJ18381-0924. The first two have very hard spectra in the Chandra band that can be described by a power law with photon indices of {Gamma}=0.6+/-0.4 and -0.7_-0.3_^+0.4^, respectively (90% confidence errors are given), and both have a unique near-IR counterpart consistent with the Chandra position. IGR J14091-6108 also displays a strong iron line and a relatively low X-ray luminosity, and we argue that the most likely source type is a cataclysmic variable (CV), although we do not completely rule out the possibility of a high mass X-ray binary. IGR J18088-2741 has an optical counterpart with a previously measured 6.84hr periodicity, which may be the binary orbital period. We also detect five cycles of a possible 800-950s period in the Chandra light curve, which may be the compact object spin period. We suggest that IGR J18088-2741 is also most likely a CV. For IGR J18381-0924, the spectrum is intrinsically softer with {Gamma}=1.5_-0.4_^+0.5^, and it is moderately absorbed, N_H_=(4+/-1)x10^22^/cm2. There are two near-IR sources consistent with the Chandra position, and they are both classified as galaxies, making it likely that IGR J18381-0924 is an active galactic nucleus. For the other five IGR sources, we provide lists of nearby Chandra sources, which may be used along with further observations to identify the correct counterparts, and we discuss the implications of the low inferred Chandra count rates for these five sources.
- ID:
- ivo://CDS.VizieR/J/ApJ/701/811
- Title:
- Chandra observations of INTEGRAL sources
- Short Name:
- J/ApJ/701/811
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on 0.3-10keV X-ray observations by the Chandra X-ray Observatory of the fields of 22 sources that were discovered as hard X-ray (20-100keV) sources by the International Gamma-Ray Astrophysics Satellite ("IGR" sources). The observations were made during Chandra's 9th observing cycle, and their purpose is to localize the sources and to measure their soft X-ray spectra in order to determine the nature of the sources. We find very likely Chandra counterparts for 18 of the 22 sources.
