- ID:
- ivo://CDS.VizieR/J/ApJ/831/145
- Title:
- 6Ms Chandra long-term analyses of AGNs
- Short Name:
- J/ApJ/831/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform long-term (~15 years, observed-frame) X-ray variability analyses of the 68 brightest radio-quiet active galactic nuclei (AGNs) in the 6Ms Chandra Deep Field-South survey; the majority are in the redshift range of 0.6-3.1, providing access to penetrating rest-frame X-rays up to ~10-30keV. Of the 68 sources, 24 are optical spectral type I AGNs, and the rest (44) are type II AGNs. The timescales probed in this work are among the longest for X-ray variability studies of distant AGNs. Photometric analyses reveal widespread photon flux variability: 90% of AGNs are variable above a 95% confidence level, including many X-ray obscured AGNs and several optically classified type II quasars. We characterize the intrinsic X-ray luminosity (L_X_) and absorption (N_H_) variability via spectral fitting. Most (74%) sources show L_X_ variability; the variability amplitudes are generally smaller for quasars. A Compton-thick candidate AGN shows variability of its high-energy X-ray flux, indicating the size of reflecting material to be <~0.3pc. L_X_ variability is also detected in a broad absorption line quasar. The N_H_ variability amplitude for our sample appears to rise as time separation increases. About 16% of sources show N_H_ variability. One source transitions from an X-ray unobscured to obscured state, while its optical classification remains type I; this behavior indicates the X-ray eclipsing material is not large enough to obscure the whole broad-line region.
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- ID:
- ivo://CDS.VizieR/J/A+A/373/63
- Title:
- M31 second ROSAT PSPC survey
- Short Name:
- J/A+A/373/63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper reports the results of the analysis of the second ROSAT PSPC survey of M 31 performed in summer 1992. We compare our results with those of the first survey, already published in Supper et al. (1997, Cat. <J/A+A/317/328>). Within the ~10.7deg^2^ field of view, 396 individual X-ray sources are detected in the second survey data, of which 164 are new detections. When combined with the first survey, this result in a total of 560 X-ray sources in the field of M 31. Their (0.1keV-2.0keV) fluxes range from 7x10^-15^erg/cm^2^/s to 7.6x10^-12^erg/cm^2^/s, and of these 560 sources, 55 are tentatively identified with foreground stars, 33 with globular clusters, 16 with supernova remnants, and 10 with radio sources and galaxies (including M 32). A comparison with the results of the Einstein M 31 survey reveals 491 newly detected sources, 11 long term variable sources, and 7 possible transient sources. Comparing the two ROSAT surveys, we come up with 34 long term variable sources and 8 transient candidates.
- ID:
- ivo://CDS.VizieR/J/ApJ/919/18
- Title:
- 1.75 Ms Ultra Narrow Deep Field Catalogue
- Short Name:
- J/ApJ/919/18
- Date:
- 07 Dec 2021
- Publisher:
- CDS
- Description:
- The present catalog summaries the results of a survey carried out on one of the deepest X-ray field observed by the XMM-Newton satellite. The survey is made by 13 observations taken over 2 years with a total exposure time of 1.75Ms (1.372Ms for flare-filtered) in a field of 30'x30' around the blazar 1ES 1553+113. Using a conservative threshold of Maximum Likelihood significance of ML>=6, we detected 301 X-ray point-sources, for which we derived positions, fluxes at different bands and hardness ratios. Thanks to an optical follow-up by the Gran Telescopio Canarias (GTC) over the same field in u'g'r'i'z' bands, we obtained an optical source list of 43,068 elements with photometric redshift. We cross correlated this optical source list and an infrared catalog obtained by WISE with photometric measurements in the W1, W2, W3 and W4 bands, with our X-ray catalog. We identified optical/IR counterpart candidates for our X-ray sources and we estimated their X-ray luminosities, redshift distribution, X-ray/optical flux ratio and absolute magnitudes. Additionally, we identify a subset of 204 AGNs, for which we classified as: Quasar, Seyfert galaxies and Low Luminous AGNs (LLAGNs), based on their luminosities.
- ID:
- ivo://CDS.VizieR/J/AJ/122/1844
- Title:
- MSX and 2MASS cross-correlation in LMC
- Short Name:
- J/AJ/122/1844
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Large Magellanic Cloud (LMC) has been observed by the Midcourse Space Experiment (MSX) in the mid-infrared and the Two Micron All Sky Survey (2MASS) in the near-infrared. We have performed a cross-correlation of the 1806 MSX catalog sources and nearly 1.4 million 2MASS catalogued point and extended sources and find 1664 matches. Using the available color information, we identify a number of stellar populations and nebulae, including main-sequence stars, giant stars, red supergiants, carbon- and oxygen-rich asymptotic giant branch (AGB) stars, planetary nebulae, H II regions, and other dusty objects likely associated with early-type stars. A total of 731 of these sources have no previous identification. We compile a listing of all objects, which includes photometry and astrometry. The 8.3{mu}m MSX sensitivity is the limiting factor for object detection: only the brighter red objects, specifically the red supergiants, AGB stars, planetary nebulae, and H II regions, are detected in the LMC. The remaining objects are likely in the Galactic foreground. The spatial distribution of the infrared LMC sources may contribute to understanding stellar formation and evolution and the overall galactic evolution. We demonstrate that a combined mid- and near-infrared photometric baseline provides a powerful means of identifying new objects in the LMC for future ground-based and space-based follow-up observations.
- ID:
- ivo://CDS.VizieR/V/114
- Title:
- MSX6C Infrared Point Source Catalog
- Short Name:
- V/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Version 2.3 of the Midcourse Space Experiment (MSX) Point Source Catalog (PSC), which supersedes the version (1.2) that was released in 1999 (Cat. V/107), contains over 100,000 more sources than the previous version. The photometry is based on co-added image plates, as opposed to single-scan data, which results in improved sensitivity and hence reliability in the fluxes. Comparison with Tycho-2 positions indicates that the astrometric accuracy of the new catalog is more than 1'' better than that in Version 1.2. In addition to the Galactic plane, Areas Missed by the Infrared Astronomical Satellite (IRAS), and the Large Magellanic Cloud, which were included in the previous catalog, Version 2.3 includes data from the Small Magellanic Cloud, eight nearby galaxies, and several molecular clouds and star forming regions. The infrared instrument on MSX was named SPIRIT III; it was a 35cm clear aperture off-axis telescope with five line scanned infrared focal plane arrays of 18.3arcsec square pixels, with a high sensitivity (0.1Jy at 8.3micron). The 6 bands are B1 (4.29micron, FWHM 4.22-4.36micron), B2 (4.25micron, 4.24-4.45micron), A (8.28micron, 6.8-10.8micron), C (12.13micron, 11.1-13.2micron), D (14.65micron, 13.5-15.9micron), and E (21.34micron, 18.2-25.1micron). The MSX catalog names of the sources have been defined according to International Astronomical Union (IAU) conventions with a unique identifier combined with the position of the source. In this case, the MSX PSC V2.3 sources are named using the convention MSX6C GLLL.llll+/-BB.bbbb, where MSX6C denotes that this is MSX data run using Version 6.0 of the CONVERT software, and GLLL.llll+/-BB.bbbb gives the Galactic coordinates of the source. (Names in the minicatalogs may differ slightly from those given in Kraemer et al. 2002AJ....124.2990K, 2003AJ....126.1423K) For ease of handling, the main catalog is broken into six files: five for the Galactic plane survey, plus the primary high latitude regions (the IRAS gaps and the LMC). The supplementary catalogs are the singleton catalog, the low-reliability catalog, and minicatalogs for 19 selected regions. All catalogs have the same format. However, the minicatalogs for the galaxies (except the SMC) and Orion do not have all the fields filled in because they were solely created from the images, not from the Point Source Extractor; there are no singleton files for these regions. Also, the minicatalogs may not have singleton or low-reliability counterparts if no sources met the inclusion criteria. All told, there are a total of 45 data files.
- ID:
- ivo://CDS.VizieR/V/107
- Title:
- MSX5C Infrared Point Source Catalog
- Short Name:
- V/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The principal objective of the astronomy experiments abroad the Midcourse Space Experiment (MSX) was to complete the census of the mid-infrared (4.2-25{mu}m) sky: the areas missed by the IRAS mission (about 4% of the sky was not surveyed by IRAS), and the Galactic Plane where the sensitivity of IRAS was degraded by confusion noise in the regions of high source densities or structured extended emission. The infrared instrument on MSX is named SPIRIT III; it is a 35cm clear aperture off-axis telescope with five line scanned infrared focal plane arrays of 18.3arcsec square pixels, with a high sensitivity (0.1Jy at 8.3{mu}m). The characteristics of the 6 bands B1, B2, A, C, D and E are summarized in the "Note (1)" below. The data are contained in 7 files according to the location on the sky: 5 are related to the Galactic Plane, one (non-plane) contains the IRAS gap catalog, the the lmc.dat file contains the observations of the Large Magellanic Cloud.
- ID:
- ivo://CDS.VizieR/J/A+A/552/A40
- Title:
- MSX high-contrast IRDCs with NH_3_
- Short Name:
- J/A+A/552/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Despite increasing research in massive star formation, little is known about its earliest stages. Infrared Dark Clouds (IRDCs) are cold, dense and massive enough to harbour the sites of future high-mass star formation. But up to now, mainly small samples have been observed and analysed. To understand the physical conditions during the early stages of high-mass star formation, it is necessary to learn more about the physical conditions and stability in relatively unevolved IRDCs. Thus, for characterising IRDCs studies of large samples are needed. We investigate a complete sample of 220 northern hemisphere high-contrast IRDCs using the ammonia (1,1)- and (2,2)-inversion transitions. We detected ammonia (1,1)-inversion transition lines in 109 of our IRDC candidates. Using the data we were able to study the physical conditions within the star-forming regions statistically. We compared them with the conditions in more evolved regions which have been observed in the same fashion as our sample sources. Our results show that IRDCs have, on average, rotation temperatures of 15K, are turbulent (with line width FWHMs around 2km/s), have ammonia column densities on the order of 10^14^cm^-2^ and molecular hydrogen column densities on the order of 10^22^cm^-2^. Their virial masses are between 100 and a few 1000M_{sun}_. The comparison of bulk kinetic and potential energies indicate that the sources are close to virial equilibrium. IRDCs are on average cooler and less turbulent than a comparison sample of high-mass protostellar objects, and have lower ammonia column densities. Virial parameters indicate that the majority of IRDCs are currently stable, but are expected to collapse in the future.
- ID:
- ivo://CDS.VizieR/II/269
- Title:
- MSX Ultraviolet Point Source Catalog
- Short Name:
- II/269
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Midcourse Space Experiment (MSX) Ultraviolet Point Source Catalog contains 47,283 point sources from a set of 201 observations that surveyed approximately half the sky and from a set of 32 pointed observations toward specific targets. For each source, we provide position, UV magnitude and uncertainty in at least one of six filters and where possible an identification of a nearby source from the SIMBAD database. If a nearby source is identified, we include its proximity to the MSX source, and if known, the spectral type and the B and V magnitudes of the SIMBAD object. There were 11,565 matches between MSX and SIMBAD objects, and we estimate false identification to be about 3%. The limiting fluxes differ from filter to filter, and range from 10^-16^erg/s/cm2/{AA} for IUN4 to 7.8*10^-12^erg/s/cm2/{AA} for IUW3. Because of variations among the observation sets, the catalog is not complete to the limiting magnitudes for the filters. The UV instrument on MSX was named UVISI (Mill et al., 1994, Journal of Spacecraft and Rockets, 31, 900 (1994JSpRo..31..900M in ADS); Carbary et al., 1994, Applied Optics, 33, 4201 (1994ApOpt..33.4201C in ADS)). The fields-of-view for the narrow-field and wide-field UV imagers were 1.46x1.19deg (detector pixels of 20.6"x17.5") and 13.4x9.2deg (detector pixels of 3.12'x2.27'), respectively. Four filters were used with the narrow-field imager (IUN) with effective wavelengths centered at 2480{AA} (IUN3), 2310{AA} (IUN4), 2230{AA} (IUN5), and 2930{AA} (IUN6). Two filters were used with the wide-field imager (IUW) and centered at 1320{AA} (IUW3) and 1560{AA} (IUW6). Two data files are available for the MSX UV Point Source Catalog: the calibration data file and the catalog data file.
- ID:
- ivo://CDS.VizieR/J/MNRAS/432/1178
- Title:
- 2MTF. HI observations of 303 southern galaxies
- Short Name:
- J/MNRAS/432/1178
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new 21-cm neutral hydrogen (HI) observations of spiral galaxies for the 2MASS Tully-Fisher (2MTF) survey. Using the 64-m Parkes radio telescope multibeam system we obtain 152 high signal to noise ratio HI spectra from which we extract 148 high-accuracy (<5% error) velocity widths and derive reliable rotation velocities. The observed sample consists of 303 southern ({delta}<-40{deg}) galaxies selected from the 2MASS Redshift Survey with Ks<11.25mag, cz<10000km/s and axis ratio b/a<0.5. The HI observations reported in this paper will be combined with new HI spectra from the Green Bank and Arecibo telescopes, together producing the most uniform Tully-Fisher survey ever constructed (in terms of sky coverage). In particular, due to its near-infrared selection, 2MTF will be significantly more complete at low Galactic latitude (|b|<15{deg}) and will provide a more reliable map of peculiar velocities in the local Universe.
- ID:
- ivo://CDS.VizieR/J/A+A/556/A55
- Title:
- Multi-color photometry of star-forming galaxies
- Short Name:
- J/A+A/556/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We estimate the galaxy stellar mass function and stellar mass density for star-forming and quiescent galaxies with 0.2<z<4. We construct a large, deep sample of galaxies selected using the new UltraVISTA DR1 data release (Cat. J/A+A/544/A156). Our analysis is based on precise 30-band photometric redshifts. By comparing these photometric redshifts with 10800 spectroscopic redshifts from the zCOSMOS bright (Cat. J/ApJS/172/70) and faint (Lilly et al. in prep) surveys, we find an accuracy of sigma(dz/(1+z))=0.008 at i<22.5 and sigma(dz/(1+z))=0.03 at 1.5<z<4.
