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561. AEGIS-X Deep survey of EGS (AEGIS-XD)
ID:
ivo://CDS.VizieR/J/ApJS/220/10
Title:
AEGIS-X Deep survey of EGS (AEGIS-XD)
Short Name:
J/ApJS/220/10
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of deep Chandra imaging of the central region of the Extended Groth Strip, the AEGIS-X Deep (AEGIS-XD) survey. When combined with previous Chandra observations of a wider area of the strip, AEGIS-X Wide (AEGIS-XW), these provide data to a nominal exposure depth of 800ks in the three central ACIS-I fields, a region of approximately 0.29deg^2^. This is currently the third deepest X-ray survey in existence; a factor ~2-3 shallower than the Chandra Deep Fields (CDFs), but over an area ~3 times greater than each CDF. We present a catalog of 937 point sources detected in the deep Chandra observations, along with identifications of our X-ray sources from deep ground-based, Spitzer, GALEX, and Hubble Space Telescope imaging. Using a likelihood ratio analysis, we associate multiband counterparts for 929/937 of our X-ray sources, with an estimated 95% reliability, making the identification completeness approximately 94% in a statistical sense. Reliable spectroscopic redshifts for 353 of our X-ray sources are available predominantly from Keck (DEEP2/3) and MMT Hectospec, so the current spectroscopic completeness is ~38%. For the remainder of the X-ray sources, we compute photometric redshifts based on multiband photometry in up to 35 bands from the UV to mid-IR. Particular attention is given to the fact that the vast majority the X-ray sources are active galactic nuclei and require hybrid templates. Our photometric redshifts have mean accuracy of {sigma}=0.04 and an outlier fraction of approximately 5%, reaching {sigma}=0.03 with less than 4% outliers in the area covered by CANDELS.
562. A faint companion around CrA-9
ID:
ivo://CDS.VizieR/J/MNRAS/502/6117
Title:
A faint companion around CrA-9
Short Name:
J/MNRAS/502/6117
Date:
21 Oct 2021
Publisher:
CDS
Description:
Understanding how giant planets form requires observational input from directly imaged protoplanets. We used VLT/NACO and VLT/SPHERE to search for companions in the transition disc of 2MASS J19005804-3645048 (hereafter CrA-9), an accreting M0.75 dwarf with an estimated age of 1-2Myr. We found a faint point source at ~0.7-arcsec separation from CrA-9 (~108au projected separation). Our 3-epoch astrometry rejects a fixed background star with a 5{sigma} significance. The near-IR absolute magnitudes of the object point towards a planetary-mass companion. However, our analysis of the 1.0-3.8um spectrum extracted for the companion suggests it is a young M5.5 dwarf, based on both the 1.13um Na index and comparison with templates of the Montreal Spectral Library. The observed spectrum is best reproduced with high effective temperature (3057^+119^_-36_K) BT-DUSTY and BT-SETTL models, but the corresponding photometric radius required to match the measured flux is only 0.60^+0.01^_-0.04_ Jovian radius. We discuss possible explanations to reconcile our measurements, including an M-dwarf companion obscured by an edge-on circum-secondary disc or the shock-heated part of the photosphere of an accreting protoplanet. Follow-up observations covering a larger wavelength range and/or at finer spectral resolution are required to discriminate these two scenarios.
563. A faint galaxy survey to B = 24.
ID:
ivo://CDS.VizieR/J/MNRAS/273/157
Title:
A faint galaxy survey to B = 24.
Short Name:
J/MNRAS/273/157
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using the multi-slit LDSS-2 spectrograph on the William Herschel Telescope we have completed a redshift survey in the magnitude range 22.5<B<24 which produced 73 redshifts representing a 73% complete sample uniformly selected from four deep fields at high galactic latitude. The survey extends to z>1 and includes the highest redshift galaxy (z=1.108) yet discovered in a field sample.
564. AFGL 2591 maps in CS, SO and HCN lines
ID:
ivo://CDS.VizieR/J/A+A/475/549
Title:
AFGL 2591 maps in CS, SO and HCN lines
Short Name:
J/A+A/475/549
Date:
21 Oct 2021
Publisher:
CDS
Description:
The chemistry in the inner few thousand AU of accreting envelopes around young stellar objects is predicted to vary greatly with far-UV and X-ray irradiation by the central star. We search for molecular tracers of high-energy irradiation by the protostar in the hot inner envelope. The Submillimeter Array (SMA) has observed the high-mass star forming region AFGL 2591 in lines of CS, SO, HCN, HCN(nu2=1), and HC^15^N with 0.6" resolution at 350GHz probing radial scales of 600-3500AU for an assumed distance of 1kpc. The SMA observations are compared with the predictions of a chemical model fitted to previous single-dish observations.
565. AFGL 2591 multi-wavelength maps
ID:
ivo://CDS.VizieR/J/A+A/551/A43
Title:
AFGL 2591 multi-wavelength maps
Short Name:
J/A+A/551/A43
Date:
21 Oct 2021
Publisher:
CDS
Description:
While it is currently unclear from a theoretical standpoint which forces and processes dominate the formation of high-mass stars, and hence determine the mode in which they form, much of the recent observational evidence suggests that massive stars are born in a similar manner to their low-mass counterparts. This paper aims to investigate the hypothesis that the embedded luminous star AFGL 2591-VLA 3 (2.3E+5L_{sun}_ at 3.33kpc) is forming according to a scaled-up version of a low-mass star formation scenario. We present multi-configuration Very Large Array 3.6cm and 7mm, as well as Combined Array for Research in Millimeter Astronomy C^18^O and 3mm continuum observations to investigate the morphology and kinematics of the ionized gas, dust, and molecular gas around AFGL 2591. We also compare our results to ancillary Gemini North near-IR images, and model the near-IR to sub-mm Spectral Energy distribution (SED) and Two Micron All Sky Survey (2MASS) image profiles of AFGL 2591 using a Monte-Carlo dust continuum radiative transfer code. The observed 3.6 cm images uncover for the first time that the central powering source AFGL 2591-VLA 3 has a compact core plus collimated jet morphology, extending 4000AU eastward from the central source with an opening angle of <10{deg} at this radius. However, at 7mm VLA 3 does not show a jet morphology, but instead compact (< 500AU) emission, some of which (<0.57mJy of 2.9mJy) is estimated to be from dust emission. The spectral index of AFGL 2591-VLA 3 between 3.6cm and 7mm was found to be between 0.4 and 0.5, similar to that of an ionized wind. If the 3.6cm emission is modelled as an ionized jet, the jet has almost enough momentum to drive the larger-scale flow. However, assuming a shock efficiency of 10%, the momentum rate of the jet is not sufficient to ionize itself via only shocks, and thus a significant portion of the emission is instead likely created in a photoionized wind. The C18O emission uncovers dense entrained material in the outflow(s) from these young stars. The main features of the SED and 2MASS images of AFGL 2591-VLA 3 are also reproduced by our model dust geometry of a rotationally flattened envelope with and without a disk. The above results are consistent with a picture of massive star formation similar to that seen for low-mass protostars. However, within its envelope, AFGL 2591-VLA 3 contains at least four other young stars, constituting a small cluster. Therefore it appears that AFGL 2591-VLA 3 may be able to source its accreting material from a shared gas reservoir while still exhibiting the phenomena expected during the formation of low-mass stars.
566. AFGL 5157 near-IR imaging
ID:
ivo://CDS.VizieR/J/AJ/117/446
Title:
AFGL 5157 near-IR imaging
Short Name:
J/AJ/117/446
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present near-infrared images of the star-forming region AFGL 5157 in the JHK broadband filters and H_2_v=1-0S(1) narrowband filter. The images reveal a dense cluster of stars and infrared nebulosities associated with previously known infrared sources. Of 54 near-infrared sources detected in the nebula, NGC 1985, 12 exhibit infrared excesses typical of T Tauri stars, Herbig Ae/Be stars, and protostars. The magnitude and color distribution of the cluster of stars in the nebula are found to be different from those outside the nebular region. The K'-magnitude distribution of the cluster is quite flat, while the noncluster is peaked toward the low magnitude. The [H-K'] color of the cluster also displays 0.3 mag redder than that of the noncluster. The infrared nebula displays a bright nucleus with two spirals extended to the north and south. In light of the color properties of the nebula, we propose a shell model for the nebular structure that could be formed by star-forming activity of the central cluster.
567. AFGL 2591-VLA 3 IRAM/NOEMA datacubes
ID:
ivo://CDS.VizieR/J/A+A/655/A84
Title:
AFGL 2591-VLA 3 IRAM/NOEMA datacubes
Short Name:
J/A+A/655/A84
Date:
10 Mar 2022 07:32:39
Publisher:
CDS
Description:
Increasing evidence suggests that, similar to their low-mass counterparts, high-mass stars form through a disk-mediated accretion process. At the same time, formation of high-mass stars still necessitates high accretion rates, and hence, high gas densities, which in turn can cause disks to become unstable against gravitational fragmentation. We study the kinematics and fragmentation of the disk around the high-mass star forming region AFGL 2591-VLA 3 which was hypothesized to be fragmenting based on the observations that show multiple outflow directions. We use a new set of high-resolution (0.19-arcsec) IRAM/NOEMA observations at 843 micron towards VLA 3 which allow us to resolve its disk, characterize the fragmentation, and study its kinematics. In addition to the 843 micron continuum emission, our spectral setup targets warm dense gas and outflow tracers such as HCN, HC_3_N and SO_2_, as well as vibrationally excited HCN lines. The high resolution continuum and line emission maps reveal multiple fragments with subsolar masses within the inner 1000AU of VLA 3. Furthermore, the velocity field of the inner disk observed at 843 micron shows a similar behavior to that of the larger scale velocity field studied in the CORE project at 1.37mm. We present the first observational evidence for disk fragmentation towards AFGL 2591-VLA 3, a source that was thought to be a single high-mass core. While the fragments themselves are low-mass, the rotation of the disk is dominated by the protostar with a mass of 10.3+/-1.8M_{sun}_. These data also show that NOEMA Band 4 can obtain the highest currently achievable spatial resolution at (sub-)mm wavelengths in observations of strong northern sources.
568. A final non-redundant catalogue for 7C 151-MHz survey
ID:
ivo://CDS.VizieR/VIII/84
Title:
A final non-redundant catalogue for 7C 151-MHz survey
Short Name:
VIII/84
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a final unified catalogue for the 7C survey at 151 MHz with resolution 70x70cosec(dec) arcsec^2^. This has been constructed by amalgamating the existing catalogues derived from individual fields imaged at this resolution and eliminating redundancy in regions of mutual overlap. This is a non-trivial procedure because the flux in multiple-component sources may be fitted differently on alternative images, owing, for example, to differences in local noise and beam distortion. The final catalogue thus produced contains 43683 sources. Separate final catalogues have been published for the 7C Galactic Plane survey (7CG, see Cat. J/MNRAS/294/607) and the lower-resolution survey of the low-declination strip 9h<RA<16h, 20deg<Dec<35deg (Cat. J/MNRAS/282/779). The individual catalogues for about 40 of the regions contributing to the total have already been published, together with full details of the methodology, in MNRAS or A&AS: Lacy et al. 1995, MNRAS, 276, 614 (=1995MNRAS.276..614L) (#92 below) Visser et al. 1995, A&AS, 110, 419 (=1995A&AS..110..419V) (#93 below) Pooley et al. 1998, MNRAS, 298, 637 (=1998MNRAS.298..637P) (#94-96 below) Riley et al. 1999, MNRAS, 306, 31 (=1999MNRAS.306...31R) (# 1-33 below) and these data are also available via the MRAO website at http://www.mrao.cam.ac.uk/surveys/7C/ Individual catalogues for the remaining 58 regions by Riley et al. (#34-91 below) were released electronically via the MRAO website in November 2001. These include a re-analysis of data originally published in rather a different parametrization by McGilchrist et al. 1990, MNRAS, 246, 110 (=1990MNRAS.246..110M) The regions re-analyzed are those numbered #41,44,59,60,62 and 63 below and they supersede McGilchrist's 1990 publication. The RAxDec coverage, average rms noise, flux density of the faintest source listed and completeness limit for each of the individual regions contributing to the final catalogue are given in the table "regions.dat". 1-sigma errors on the listed source positions may be approximated by: RA..error(arcsec) = SQRT(1.0**2 + (32/SNR)**2) Dec.error(arcsec) = Kcosec(dec) x (RA error) where (approx) K= 1.0 around dec 70, increasing to 1.3 below dec 50, and 1-sigma errors on the listed flux densities may be approximated by: Error on S beam-fitted(Jy) = SQRT(0.03**2 + SNR**-2) x S(Jy) Error on SINT(Jy) = 1.5 x SQRT(0.03**2 + SNR**-2) x SINT(Jy) where SNR, S and SINT correspond to the columns denoted by those names in the byte-by-byte description below. For multi-component sources the SNR for the brightest component is used to estimate the SINT error. For further details of the surveys and data analysis procedures please refer to the published papers referenced at the head of this file and references therein.
569. A Finding List of Faint UV-Bright Stars
ID:
ivo://CDS.VizieR/II/212A
Title:
A Finding List of Faint UV-Bright Stars
Short Name:
II/212A
Date:
21 Oct 2021
Publisher:
CDS
Description:
195 UV-bright stars have been found on two-color 48-inch Schmidt plates centered on the galactic plane, and on one high-latitude plate. This catalog contains sources with (U-B) in the range U-B=0 to U-B=-1.5.
570. A Finding List of Faint UV-Bright Stars
ID:
ivo://CDS.VizieR/II/231
Title:
A Finding List of Faint UV-Bright Stars
Short Name:
II/231
Date:
21 Oct 2021
Publisher:
CDS
Description:
The survey lists the very blue objects found on the plates taken for the Sandage Two-Color Survey of the Galactic Plane obtained using the Palomar 48 inch Oschin Schmidt telescope. The sources range in U-B color from U-B~-0.1 to U-B~-1.0 and in magnitude from m_B_~10 to ~20.

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