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2341. SIGMA: Keck spectra of z~2 gal. in CANDELS fields
ID:
ivo://CDS.VizieR/J/ApJ/830/14
Title:
SIGMA: Keck spectra of z~2 gal. in CANDELS fields
Short Name:
J/ApJ/830/14
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from a survey of the internal kinematics of 49 star-forming galaxies at z~2 in the CANDELS fields with the Keck/MOSFIRE spectrograph, Survey in the near-Infrared of Galaxies with Multiple position Angles (SIGMA). Kinematics (rotation velocity V_rot_ and gas velocity dispersion {sigma}_g_) are measured from nebular emission lines which trace the hot ionized gas surrounding star-forming regions. We find that by z~2, massive star-forming galaxies (logM_*_/M_{sun}_>~10.2) have assembled primitive disks: their kinematics are dominated by rotation, they are consistent with a marginally stable disk model, and they form a Tully-Fisher relation. These massive galaxies have values of V_rot_/{sigma}_g_ that are factors of 2-5 lower than local well-ordered galaxies at similar masses. Such results are consistent with findings by other studies. We find that low-mass galaxies (logM_*_/M_{sun}_<~10.2) at this epoch are still in the early stages of disk assembly: their kinematics are often dominated by gas velocity dispersion and they fall from the Tully-Fisher relation to significantly low values of V_rot_. This "kinematic downsizing" implies that the process(es) responsible for disrupting disks at z~2 have a stronger effect and/or are more active in low-mass systems. In conclusion, we find that the period of rapid stellar mass growth at z~2 is coincident with the nascent assembly of low-mass disks and the assembly and settling of high-mass disks.
2342. sigma Ori GTC+INT spectroscopy
ID:
ivo://CDS.VizieR/J/A+A/629/A114
Title:
sigma Ori GTC+INT spectroscopy
Short Name:
J/A+A/629/A114
Date:
21 Oct 2021
Publisher:
CDS
Description:
Only a few open clusters are as important for the study of stellar and substellar objects, and their formation and evolution, as the young sigma Orionis cluster. However, a complete spectroscopic characterisation of its whole stellar population is still missing. We filled most of that gap with a large spectroscopic and astrometric survey of targets towards sigma Orionis. Eventually, it will be one of the open clusters with the lowest proportion of interlopers and the largest of confirmed cluster members with known uncontrovertible youth features. We acquired 317 low-resolution optical spectra with IDS at the 2.5m Isaac Newton Telescope and OSIRIS at the 10.4m Gran Telescopio Canarias. On them, we measured equivalent widths of LiI, H{alpha}, and other key lines, and determined spectral types. We complemented the information with Gaia DR2 astrometric data and other features of youth (mid-infrared excess, X-ray emission) compiled with Virtual Observatory tools and from the literature. Of the 168 observed targets, we determined for the first time spectral types of 39 stars and equivalent widths of LiI and H{alpha} of 34 and 12 stars, respectively. We identified 11 close ({rho}<~3-arcsec) binaries resolved by Gaia, of which three are new, 14 strong accretors, of which four are new and another four have H{alpha} emission shifted by over 120km/s, two juvenile star candidates in the sparse population of the Ori OB1b association, and one spectroscopic binary candidate. Remarkably, we found 51 cluster non-members, 35 of which were previously considered as sigma Orionis members and taken into account in high-impact works on, e.g., disc frequency and initial mass function.
2343. Signatures of an incipient hot corino in B1b-S
ID:
ivo://CDS.VizieR/J/A+A/620/A80
Title:
Signatures of an incipient hot corino in B1b-S
Short Name:
J/A+A/620/A80
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Barnard 1b core shows signatures of being at the earliest stages of low- mass star formation, with two extremely young and deeply embedded proto- stellar objects. Hence, this core is an ideal target to study the structure and chemistry of the first objects formed in the collapse of prestellar cores. We present ALMA Band 6 spectral line observations at ~0.6" of angular resolution towards Barnard 1b. We have extracted the spectra towards both protostars, and used a local thermodynamic equilibrium (LTE) model to reproduce the observed line profiles. B1b-S shows rich and complex spectra, with emission from high energy transitions of complex molecules, such as CH_3_OCOH and CH_3_CHO, including vibrational level transitions. We have tentatively detected for the first time in this source emission from NH_2_CN, NH_2_CHO, CH_3_CH_2_OH, CH_2_OHCHO, CH_3_CH_2_OCOH and both aGg' and gGg' conformers of (CH_2_OH)_2_. This is the first detection of ethyl formate (CH_3_CH_2_OCOH) towards a low-mass star forming region. On the other hand, the spectra of the FHSC candidate B1b-N are free of COMs emission. In order to fit the observed line profiles in B1b-S, we used a source model with two components: an inner hot and compact component (200K, 0.35") and an outer and colder one (60K, 0.6"). The resulting COM abundances in B1b-S range from 10^-13^ for NH_2_CN and NH_2_CHO, up to 10^-9^ for CH_3_OCOH. Our ALMA Band 6 observations reveal the presence of a compact and hot component in B1b-S, with moderate abundances of complex organics. These results indicate that a hot corino is being formed in this very young Class 0 source.
2344. SiIV absorption systems
ID:
ivo://CDS.VizieR/J/ApJ/729/87
Title:
SiIV absorption systems
Short Name:
J/ApJ/729/87
Date:
21 Oct 2021
Publisher:
CDS
Description:
We identified 24 SiIV absorption systems with z<~1 from a blind survey of 49 low-redshift quasars with archival Hubble Space Telescope ultraviolet spectra. We relied solely on the characteristic wavelength separation of the doublet to automatically detect candidates. After visual inspection, we defined a sample of 20 definite (group G=1) and 4 "highly likely" (G=2) doublets with rest equivalent widths W_r_ for both lines detected at >=3{sigma}_W_r__.
2345. SiIV and NV absorption line SDSS quasar systems
ID:
ivo://CDS.VizieR/J/ApJS/243/2
Title:
SiIV and NV absorption line SDSS quasar systems
Short Name:
J/ApJS/243/2
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using the quasar spectra from the Sloan Digital Sky Survey and with variable C IV absorption line systems, we measure the Si IV and N V absorption line systems. We obtain 50 variable Si IV absorption line systems and 39 variable N V absorption line systems. We find that the variations in most of the C IV, Si IV, and N V absorption lines are correlated with the changes in quasar continuum. In addition, a significant portion of the variable absorption lines are the consistent variations of multiple systems with large velocity separations. Therefore, the variations of the C IV, Si IV, and N V absorption lines could be mainly driven by the changes in quasar radiations, which cause changes in ionization states or column densities of absorbing gas. We also find that the variable C IV, Si IV, and N V absorption line systems can be divided into low-ionization systems and high-ionization systems. The former positively responds to the changes in the quasar's brightness, and the later is the oppositive case.
2346. Simulated IR spectra of PN Hubble 12
ID:
ivo://CDS.VizieR/J/A+A/655/A46
Title:
Simulated IR spectra of PN Hubble 12
Short Name:
J/A+A/655/A46
Date:
10 Mar 2022 07:09:39
Publisher:
CDS
Description:
We present a visible-infrared imaging study of young planetary nebula (PN) Hubble 12 (Hb 12; PN G111.8-02.8) obtained with Hubble Space Telescope (HST) archival data and our own Canada-France-Hawaii Telescope (CFHT) measurements. Deep HST and CFHT observations of this nebula reveal three pairs of bipolar structures and an arc-shaped filament near the western waist of Hb 12. The existence of nested bipolar lobes together with the presence of H2 knots suggests that these structures originated from several mass-ejection events during the pre-PN phase. To understand the intrinsic structures of Hb 12, a three-dimensional model enabling the visualisation of this PN at various orientations was constructed. The modelling results show that Hb 12 may resemble other nested hourglass nebulae, such as Hen 2-320 and M 2-9, suggesting that this type of PN may be common and the morphologies of PNs are not so diverse as is shown by their visual appearances. The infrared spectra show that this PN has a mixed chemistry. We discuss the possible material that may cause the unidentified infrared emissions. The analyses of the infrared spectra and the spectral energy distribution suggest the existence of a cool companion in the nucleus of this object.
2347. Simulated spectral evolution of black holes
ID:
ivo://CDS.VizieR/J/MNRAS/454/3771
Title:
Simulated spectral evolution of black holes
Short Name:
J/MNRAS/454/3771
Date:
21 Oct 2021
Publisher:
CDS
Description:
Massive black hole (MBH) seeds at redshift z>~10 are now thought to be key ingredients to explain the presence of the supermassive (10^9-10^M_{sun}_) black holes in place <1Gyr after the big bang. Once formed, massive seeds grow and emit copious amounts of radiation by accreting the left-over halo gas; their spectrum can then provide crucial information on their evolution. By combining radiation-hydrodynamic and spectral synthesis codes, we simulate the time-evolving spectrum emerging from the host halo of a MBH seed with initial mass 10^5^M_{sun}_, assuming both standard Eddington-limited accretion, or slim accretion discs, appropriate for super-Eddington flows. The emission occurs predominantly in the observed infrared-submm (1-1000{mu}m) and X-ray (0.1-100keV) bands. Such signal should be easily detectable by JWST around ~1{mu}m up to z~25, and by ATHENA (between 0.1 and 10keV, up to z~15). Ultra-deep X-ray surveys like the Chandra Deep Field South could have already detected these systems up to z~15. Based on this, we provide an upper limit for the z>~6 MBH mass density of {rho}{blackdot}<~2.5x10^2^M_{sun}_/Mpc^3^ assuming standard Eddington-limited accretion. If accretion occurs in the slim disc mode the limits are much weaker, {rho}{blackdot}<~7.6x10^3^M_{sun}_/Mpc^3^ in the most constraining case.
2348. SINFONI K-band observations of IRS54(YLW52)
ID:
ivo://CDS.VizieR/J/A+A/552/L2
Title:
SINFONI K-band observations of IRS54(YLW52)
Short Name:
J/A+A/552/L2
Date:
21 Oct 2021
Publisher:
CDS
Description:
Molecular outflows from very low-mass stars (VLMSs) and brown dwarfs have been studied very little. So far, only a few CO outflows have been observed, allowing us to map the immediate circumstellar environment. We present the first spatially resolved H_2_ emission around IRS54 (YLW52), a ~0.1-0.2M_{sun}_ Class I source. By means of VLT SINFONI K-band observations, we probed the H2 emission down to the first ~50AU from the source. The molecular emission shows a complex structure delineating a large outflow cavity and an asymmetric molecular jet. Thanks to the detection of several H_2_transitions, we are able to estimate average values along the jet-like structure (from source position to knot D) of Av~28mag, T~2000-3000K, and H_2_column density N(H_2)~1.7x10^17cm^-2. This allows us to estimate a mass loss rate of ~2x10^-10M_{sun}_/yr for the warm H_2_component . In addition, from the total flux of the Br gamma line, we infer an accretion luminosity and mass accretion rate of 0.64L_{sun}_ and ~3x10^-7M_{sun}_/yr, respectively. The outflow structure is similar to those found in low-mass Class I and CTTS. However, the Lacc/Lbol ratio is very high (~80%), and the mass accretion rate is about one order of magnitude higher when compared to objects of roughly the same mass, pointing to the young nature of the investigated source.
2349. SINS survey of high-redshift galaxies
ID:
ivo://CDS.VizieR/J/ApJ/706/1364
Title:
SINS survey of high-redshift galaxies
Short Name:
J/ApJ/706/1364
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the Spectroscopic Imaging survey in the near-infrared (near-IR) with SINFONI (SINS) of high-redshift galaxies. With 80 objects observed and 63 detected in at least one rest-frame optical nebular emission line, mainly H{alpha}, SINS represents the largest survey of spatially resolved gas kinematics, morphologies, and physical properties of star-forming galaxies at z~1-3. We describe the selection of the targets, the observations, and the data reduction. We then focus on the "SINS H{alpha} sample," consisting of 62 rest-UV/optically selected sources at 1.3<z<2.6 for which we targeted primarily the H{alpha} and [NII] emission lines. Only ~30% of this sample had previous near-IR spectroscopic observations. The galaxies were drawn from various imaging surveys with different photometric criteria; as a whole, the SINS H{alpha} sample covers a reasonable representation of massive M_*_>~10^10^M_{sun}_ star-forming galaxies at z~1.5-2.5, with some bias toward bluer systems compared to pure K-selected samples due to the requirement of secure optical redshift. The H{alpha} morphologies tend to be irregular and/or clumpy. About one-third of the SINS H{alpha} sample galaxies are rotation-dominated yet turbulent disks, another one-third comprises compact and velocity dispersion-dominated objects, and the remaining galaxies are clear interacting/merging systems; the fraction of rotation-dominated systems increases among the more massive part of the sample.
2350. SiO maser emission in evolved stars
ID:
ivo://CDS.VizieR/J/A+A/642/A213
Title:
SiO maser emission in evolved stars
Short Name:
J/A+A/642/A213
Date:
21 Oct 2021
Publisher:
CDS
Description:
We aim to study the time evolution of the SiO maser lines in Mira-type and semi-regular variables at short timescales. We observed the SiO maser lines at 7mm and 3mm using the 40m Yebes antenna and the 30m IRAM telescope, respectively, with a minimum spacing of 1 day. We studied the semi-regular variables RX Boo and RT Vir and the Mira-type variables U Her, R LMi, R Leo, and chi Cyg.

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