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441. Accurate wavelengths in the Sun spectrum
ID:
ivo://CDS.VizieR/J/A+AS/131/431
Title:
Accurate wavelengths in the Sun spectrum
Short Name:
J/A+AS/131/431
Date:
21 Oct 2021
Publisher:
CDS
Description:
Central line wavelengths in the spectrum of the Sun observed at the centre of the disc, and in the flux spectrum, line identification and solar log(gf).
442. A census of the near-by Psc-Eri stellar stream
ID:
ivo://CDS.VizieR/J/A+A/638/A9
Title:
A census of the near-by Psc-Eri stellar stream
Short Name:
J/A+A/638/A9
Date:
21 Oct 2021
Publisher:
CDS
Description:
Within a sphere of 400pc radius around the Sun, we search for members of the Pisces-Eridanus (Psc-Eri) stellar stream in the Gaia Data Release 2 DR2) data set. We compare basic astrophysical characteristics of the stream with those of the Pleiades. We used a modified convergent-point method to identify stars with 2D - velocities consistent with the space velocity of the Psc-Eri stream and the Pleiades, respectively. We found 1387 members of the Psc-Eri stream in a G-magnitude range from 5.1mag to 19.3mag at distances between 80 and 380pc from the Sun. The stream has a nearly cylindrical shape with a length of at least 700pc and a thickness of 100pc. The accumulated stellar mass of the 1387 members amounts to about 770M_{sun}_, and the stream is gravitationally unbound. For the stream we found an age of about 135Myr. In many astrophysical properties Psc-Eri is comparable to the open cluster M45 (the Pleiades): in its age, its luminosity function (LF), its present-day mass function (PDMF) as well as in its total mass. Nonetheless, the two stellar ensembles are completely unlike in their physical appearance. We cautiously give two possible explanations for this disagreement: (i) the star-formation efficiency in their parental molecular clouds was higher for the Pleiades than for Psc-Eri or/and (ii) the Pleiades had a higher primordial mass segregation immediately after the expulsion of the molecular gas of the parental cloud.
443. Acetaldehyde CH_2_DCOH and CH_3_COD
ID:
ivo://CDS.VizieR/J/A+A/624/A70
Title:
Acetaldehyde CH_2_DCOH and CH_3_COD
Short Name:
J/A+A/624/A70
Date:
21 Oct 2021
Publisher:
CDS
Description:
Detection of deuterated species may provide information on the evolving chemistry in the earliest phases of star-forming regions. For molecules with two isomeric forms of the same isotopic variant, gas-phase and solid-state formation pathways can be differentiated using their abundance ratio. Spectroscopic databases for astrophysical purposes are built for the two mono deuterated isomeric species CH_2_DCOH and CH_3_COD of the complex organic molecule acetaldehyde. These databases can be used to search and detect these two species in astrophysical surveys, retrieving their column density and therefore abundances. Submillimeter wave and terahertz transitions were measured for mono deuterated acetaldehyde CH2DCOH which is a non-rigid species displaying internal rotation of its asymmetrical CH_2_D methyl group. An analysis of a dataset consisting of previously measured microwave data and the newly measured transition was carried out with a model accounting for the large amplitude torsion. The frequencies of 2556 transitions are reproduced with a unitless standard deviation of 2.3 yielding various spectroscopic constants. Spectroscopic databases for astrophysical purposes were built for CH_2_DCOH using the results of the present analysis and for CH_3_COD using the results of a previous spectroscopic investigation. These two species were both searched for and are detected toward a low-mass star-forming region. We report the first detection of CH2DCOH (93 transitions) and the detection of CH_3_COD (43 transitions) species in source B of the IRAS 16293-2422 young stellar binary system located in the {rho} Ophiuchus cloud region, using the publicly available ALMA Protostellar Interferometric Line Survey.
444. AC114 galaxy cluster dynamical analysis
ID:
ivo://CDS.VizieR/J/MNRAS/452/3304
Title:
AC114 galaxy cluster dynamical analysis
Short Name:
J/MNRAS/452/3304
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a dynamical analysis of the galaxy cluster AC114 based on a catalogue of 524 velocities. Of these, 169 (32 percent) are newly obtained at European Southern Observatory (Chile) with the Very Large Telescope and the VIsible MultiObject spectrograph. Data on individual galaxies are presented and the accuracy of the measured velocities is discussed. Dynamical properties of the cluster are derived. We obtain an improved mean redshift value z=0.31665+/-0.0008 and velocity dispersion {sigma}=1893^+73^_-82_km/s. A large velocity dispersion within the core radius and the shape of the infall pattern suggests that this part of the cluster is in a radial phase of relaxation with a very elongated radial filament spanning 12000km/s. A radial foreground structure is detected within the central 0.5h^-1^Mpc radius, recognizable as a redshift group at the same central redshift value. We analyse the colour distribution for this archetype Butcher-Oemler galaxy cluster and identify the separate red and blue galaxy sequences. The latter subset contains 44 percent of confirmed members of the cluster, reaching magnitudes as faint as R_f_=21.1 (1.0mag fainter than previous studies). We derive a mass M_200_=(4.3+/-0.7)x10^15^M_{sun}_h^-1^. In a subsequent paper, we will utilize the spectral data presented here to explore the mass-metallicity relation for this intermediate redshift cluster.
445. A Chandra X-ray observation of L1251B
ID:
ivo://CDS.VizieR/J/ApJ/694/425
Title:
A Chandra X-ray observation of L1251B
Short Name:
J/ApJ/694/425
Date:
21 Oct 2021
Publisher:
CDS
Description:
I report the results of a 60ks X-ray observation of the L1251 dark cloud in Cepheus, which was acquired with the ACIS-I camera on board the Chandra X-Ray Observatory. Forty-three compact X-ray sources were detected. The field of view was centered on the position of IRAS 22376+7455, an embedded Class 0/I protostar that is closely associated with the bright CO emission core, L1251B-Core E. A very intense impulsive X-ray flare was observed from a location within the formal error ellipse of the IRAS source and in close proximity (within <~1") to a thermal continuum radio source, VLA 3. Given their small spatial offsets, the radio, far-infrared, and X-ray objects appear to be identical and consequently the likely origin and driving source of high-velocity gas flows that are observed in L1251B.
446. ACIS-I observations of NGC 2264
ID:
ivo://CDS.VizieR/J/A+A/455/903
Title:
ACIS-I observations of NGC 2264
Short Name:
J/A+A/455/903
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper's goal is to improve the member census of the NGC 2264 star-forming region and study the origin of X-ray activity in young PMS stars. We analyze a deep, 100ks long, Chandra ACIS observation covering a 17'x17' field in NGC 2264. The preferential detection in X-rays of low-mass PMS stars gives strong indications of their membership. We study X-ray activity as a function of stellar and circumstellar characteristics by correlating the X-ray luminosities, temperatures, and absorptions with optical and near-infrared data from the literature.
447. Ackermann red stars
ID:
ivo://CDS.VizieR/II/260
Title:
Ackermann red stars
Short Name:
II/260
Date:
21 Oct 2021
Publisher:
CDS
Description:
In the late 1960s Gerhard Ackermann published two lists of extremely red stars (1968ZA.....69..130A and 1970A&A.....8..315A), including what appeared to be reliable spectral classifications for a few hundred stars. The two published papers provide details of the observing and analysis, made between June and October 1968 at the Heidelberg observatory with the 25cm f/3.6 Schmidt camera together with a 10-degree UBK7 prism yielding a dispersion of 3500 {AA}/mm at the atmospheric A band (7700{AA}). Exposures on ammonia-hypersensitized Kodak I-N emulsion + RG665 filter were obtained along with direct plates on I-N emulsion as well as 103a-E + OG550, totalling 101 exposures in all. The spectra were classified by following the precepts of Cameron & Nassau (1955ApJ...122..177C) and Nassau & Velghe (1964ApJ...139..190N). Ackermann initiated photoelectric observations at I and K, but obviously the Heidelberg weather was not conducive to pursuing this. Because the calibration of the photometry on the direct plates was by necessity rather crude, Ackermann's photometric results are not reported here -- the procedures used were sufficient to identify the reddest stars, but not for much else. Approximate V magnitudes were added for all the stars -- for the most part these are merely averages of the photo-blue and -red magnitudes in both GSC-2.2 and USNO-B1.0, but their zero-point and scale should be reliable at the few-tenths magnitude level in this range. Coordinates were drawn from either UCAC2 or 2MASS depending mainly on Declination, since UCAC2 extends only to about +40 Dec in this area. The UCAC2 positions should be good to better than 0.1", and those from 2MASS to 0.2". In a few cases, such as gross overexposure in 2MASS, positions are from various Schmidt survey catalogues, as indicated with each entry. The first 13 stars of the catalog come from the concluding volume of the ZA paper; in the 1970 paper, Ackermann refers to these stars using the acronym HDK, which is adopted here. The published table gave rather rough arcminute-precision positions (for equinox 1965). Star 6 was recovered 1 degree east of the nominal place, and identified with the variable star WX CMi. Along with the positions and IDs, the table shows V magnitudes and the spectral types given in the original paper. Some of the stars are within the region covered by the ASAS-3 survey, so reliable V magnitudes are available along with beautiful lightcurves. Ackermann's second much longer list contains rough photometry from the POSS-I prints for some 400 very red stars in the Cygnus starcloud, and for 254 of these spectral types were also determined. The stars without spectral classifications comprise a diverse group including both red/reddened late-type stars and greatly obscured hotter stars, but no real astrophysical information is given for any of them beyond sheer redness -- these stars are omitted from the catalog. In consultation with Prof Ackermann, the following changes have been made to the spectral types: for stars shown in the original table with a hyphen between two types (e.g. M5-M6), this was to show that the type was uncertain to that degree (i.e. M5 or M6), for which the 'slash' notation of Nancy Houk was preferred, and thus M5-M6 becomes M5/6. One star, 78-0-144, exhibited a range in types, and it is shown as M7-M9. Ackermann also indicated a number of stars as being of very-late type with VO present (separable from the A-band), but where the star was too faint to classify accurately. He agrees these are likely to be in the range M7 to M9, and again these are shown in the slash-style notation as M7/9:, with the colon added to indicate uncertainty since the types were not explicit in the original, and sometimes a question mark for those already marked as uncertain in the original. These changes were made so that machine parsing schemes will be better able to handle the classifications.
448. A classifier for spurious astrometric solutions in Gaia EDR3
ID:
ivo://org.gavo.dc/gedr3spur/q/main
Title:
A classifier for spurious astrometric solutions in Gaia EDR3
Short Name:
gedr3spur.main
Date:
15 Aug 2024 15:17:01
Publisher:
The GAVO DC team
Description:
This table contains estimates of the "fidelity" of Gaia eDR3 astrometric solutions, a measure of the likelihood the eDR3 solution is physical rather than spurious obtained using a neural network trained on a small, hand-selected sample.
449. A cluster of compact radio sources in W40
ID:
ivo://CDS.VizieR/J/AJ/140/968
Title:
A cluster of compact radio sources in W40
Short Name:
J/AJ/140/968
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present deep 3.6 cm radio continuum observations of the HII region W40 obtained using the Very Large Array (VLA) in its A and B configurations. We detect a total of 20 compact radio sources in a region of 4'x4', with 11 of them concentrated in a band with 30" of extent. We also present JHK photometry of the W40 cluster taken with the QUIRC instrument on the University of Hawaii 2.2m telescope. These data reveal that 15 of the 20 VLA sources have infrared counterparts, and 10 show radio variability with periods less than 20 days. Based on these combined radio and IR data, we propose that eight of the radio sources are candidate ultracompact HII regions, seven are likely to be young stellar objects, and two may be shocked interstellar gas.
450. ACO 1825 and AC 114 EROs photometry
ID:
ivo://CDS.VizieR/J/A+A/477/55
Title:
ACO 1825 and AC 114 EROs photometry
Short Name:
J/A+A/477/55
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the properties and nature of extremely red galaxies (ERO, R-K>=5.6) found behind two lensing clusters and compare them with other known galaxy populations. New HST/ACS, Spitzer (IRAC and MIPS), and Chandra/ACIS observations of the two lensing clusters Abell 1835 and AC 114 (ACCG 114) have been obtained, combined with our earlier optical and near-IR observations and used to study EROs in these deep fields.

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