- ID:
- ivo://CDS.VizieR/J/ApJS/250/23
- Title:
- AstroSat/UVIT and Chandra X-ray sources in M31
- Short Name:
- J/ApJS/250/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An ultraviolet (UV) survey of M31 has been carried out during 2017-19 with the Ultra-Violet Imaging Telescope (UVIT) instrument on board the AstroSat Observatory. Here we match the M31 UVIT source catalog with the Chandra source catalog. We find 67 UVIT/Chandra sources detected in a varying number of UV and X-ray bands. The UV and X-ray photometry is analyzed using power-law and blackbody models. The X-ray types include 15 low-mass X-ray binaries (LMXBs) and five active galactic nuclei. Crossmatches with catalogs of stars, clusters, and other source types yield the following: 20 of the UVIT/Chandra sources match with M31 globular clusters, and nine with foreground stars. Three more globular clusters and two more foreground stars are consistent with the UVIT source positions although outside the Chandra match radius of 1". The UV emission of the UVIT/Chandra sources associated with globular clusters is consistent with emission from blue horizontal branch stars rather than from the X-ray source. The LMXBs in globular clusters are among the most luminous globular clusters in M31. Comparison with stellar evolutionary tracks shows that the UVIT/Chandra sources with high UV blackbody temperatures are consistent with massive (10-30M_{sun}_) stars in M31.
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- ID:
- ivo://CDS.VizieR/J/A+A/592/A42
- Title:
- A study of dust nucleation in Mira. Part I.
- Short Name:
- J/A+A/592/A42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dust is efficiently produced by cool giant stars, but the condensation of inorganic dust is poorly understood. Observations of key aluminum bearing molecules around evolved stars has enabled us to investigate the nucleation of alumina (Al_2_O_3_) dust in the gas. Aims. We aim to identify and characterize aluminum bearing species in the circumstellar gas of Mira (o Ceti) in order to elucidate their role in the production of Al_2_O_3_ dust. We used multiepoch spectral line observations at (sub-)millimeter, far-infrared, and optical wavelengths including: maps with ALMA that probe the gas distribution in the immediate vicinity of the star at ~30mas; observations with ALMA, APEX, and Herschel in 2013-2015 for studying cycle and inter-cycle variability of the rotational lines of Al-bearing molecules; optical records as far back as 1965 to examine variations in electronic transitions over time spans of days to decades; and velocity measurements and excitation analysis of the spectral features that constrain the physical parameters of the gas.
- ID:
- ivo://CDS.VizieR/J/AJ/83/1549
- Title:
- A study of field galaxies. I.
- Short Name:
- J/AJ/83/1549
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As a first step towards a redetermination of the luminosity function and space distribution of field galaxies, we present data on a magnitude limited sample of galaxies in eight fields in the north and south galactic polar caps. Redshifts, accurate to about 100 km/s have been obtained for 164 of 184 galaxies brighter than J=15.0 (B~15.5) We have also measured magnitudes and colors for a large sample of 807 galaxies, complete to J~15.7.
- ID:
- ivo://CDS.VizieR/J/AJ/156/61
- Title:
- A study of the H{alpha} variability of Be stars
- Short Name:
- J/AJ/156/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the results of 4 years of high-resolution spectral observations of 69 emission-line stars, 54 of them being newly discovered sources. We classified the stars on the basis of their position in the two-color IR diagram and some additional criteria: shape and width of the H{alpha} profile, presence of He lines, proper motion and parallax, membership to open cluster and associations. Sixty of our targets turned out to be Be stars. We also found four late giants, four pre-MS stars, and one late dwarf. The H{alpha} emission profiles of our Be stars range from single peaked to typical shell profiles that can also be highly asymmetric or single-peaked profiles with a narrow absorption core. The emission profiles appear almost constant with time or highly variable in intensity and in their V/R ratio. The detected long-term variability of the H{alpha} emission is important for investigating the on/off switch phenomenon of Be stars. Our study led to an increase of the number of the emission-line stars of 16 open clusters.
- ID:
- ivo://CDS.VizieR/J/PAZh/25/115
- Title:
- A study of the open cluster NGC 6811
- Short Name:
- J/PAZh/25/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 191 individual measurements of radial velocities made with CORAVEL-type spectrometer are presented for 60 stars in the large region of NGC 6811 open cluster. Photoelectric UBVR magnitudes are given for 117 stars - members of the cluster by proper motions. Spectral classification of these stars is taken from Straizys and Kazlauskas (1993BaltA...2....1S).
- ID:
- ivo://CDS.VizieR/J/A+AS/137/351
- Title:
- A supergiants UV and visible spectra
- Short Name:
- J/A+AS/137/351
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is the first of a series whose aim is to perform a systematic study of A-type supergiant atmospheres and winds. Here we present a spectral atlas of 41 A-supergiants observed by us in high and medium resolution in the visible and ultraviolet. The atlas consists of profiles of the H{alpha}, H{beta}, H{gamma}, H{delta}, H{epsilon}, Ca II (H and K), Na I (D1 and D2), Mg II_4481_, Mg II [uv1] and Fe II [uv1, uv2, uv3, uv62, uv63, uv161] lines for 41 stars with spectral types ranging from B9 to A9 and luminosity classes Ia, Iab and Ib, and provides the basic data for a thoughtful study of these stars. The overall characteristics of the sample as well as the data reduction procedures are described. We also present some examples of spectral variability.
- ID:
- ivo://CDS.VizieR/J/ApJ/784/154
- Title:
- A survey for H{alpha} pulsar bow shocks
- Short Name:
- J/ApJ/784/154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a survey for H{alpha} bow shock emission around nearby {gamma}-detected energetic pulsars. This survey adds three Balmer-dominated neutron star bow shocks to the six previously confirmed examples. In addition to the shock around Fermi pulsar PSR J1741-2054, we now report H{alpha} structures around two additional {gamma}-ray pulsars, PSR J2030+4415 and PSR J1509-5850. These are the first known examples of H{alpha} nebulae with pre-ionization halos. With new measurements, we show that a simple analytic model can account for the angular size and flux of the bow shocks' apices. The latter, in particular, provides a new pulsar probe and indicates large moments of inertia and smaller distances than previously assumed in several cases. In particular, we show that the re-measured PSR J0437-4715 shock flux implies I=(1.7+/-0.2)x10^45^/(f_H I_sin i)g cm^2^. We also derive a distance d~0.72 kpc for the {gamma}-ray only pulsar PSR J2030+4415 and revised distances for PSRs J1959+2048 (1.4 kpc) and J2555+6535 (~1 kpc), smaller than the conventional DM-estimated values. Finally, we report upper limits for 94 additional LAT pulsars. An estimate of the survey sensitivity indicates that for a warm neutral medium filling factor {phi}_WNM_~0.3 there should be a total of approximately nine H{alpha} bow shocks in our LAT-targeted survey; given that seven such objects are now known, a much larger {phi}_WNM_ seems problematic.
- ID:
- ivo://CDS.VizieR/J/A+A/487/539
- Title:
- A survey for quasars near quasars - QNQ
- Short Name:
- J/A+A/487/539
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of our slitless spectroscopic survey for quasars near 18 known high-redshift quasars (QNQ). The three tables list the survey fields (26.2'x33.5'), the newly confirmed quasars and the remaining unconfirmed quasar candidates, respectively. For each confirmed quasar we give the equatorial coordinates, the redshift measured from the follow-up slit spectra, the redshift uncertainty and the Johnson B magnitude with uncertainty. The redshift uncertainty has been determined from the redshift dispersions of several emission lines. For the remaining candidates we list the equatorial coordinates, the approximate V magnitude, the redshift based on the slitless spectrum and our assessment of the redshift confidence.
- ID:
- ivo://CDS.VizieR/J/A+AS/113/539
- Title:
- A survey of carbon stars in the SMC
- Short Name:
- J/A+AS/113/539
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A survey of carbon stars in the outer parts of the Small Magellanic Cloud has been completed; the candidate objects were identified by inspecting UK Schmidt Telescope objective-prism plates which cover a total area of ~220 sq deg on the sky, including the inter-Cloud region. Co-ordinates are given for 1185 newly identified carbon stars.
- ID:
- ivo://CDS.VizieR/J/A+AS/31/439
- Title:
- A Survey of HII Regions in M31
- Short Name:
- J/A+AS/31/439
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An H-alpha survey, using a focal reducer and narrow-band interference filters, has resulted in the detection of nearly a thousand HII regions in M31. The catalog gives their positions, dimensions, and surface brightnesses. The surface brightnesses are on an absolute scale; the photographic measures were calibrated by using photoelectric measures from two different sources. The detection limit reached corresponds to an emission measure of 40cm^-6^pc at a temperature of 10000K.
