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721. ALMA 870um obs. of HerMES galaxies
ID:
ivo://CDS.VizieR/J/ApJ/812/43
Title:
ALMA 870um obs. of HerMES galaxies
Short Name:
J/ApJ/812/43
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Herschel Multi-tiered Extragalactic Survey (HerMES, Oliver et al. 2012, VIII/95) has identified large numbers of dusty star-forming galaxies (DSFGs) over a wide range in redshift. A detailed understanding of these DSFGs is hampered by the limited spatial resolution of Herschel. We present 870{mu}m 0.45" resolution imaging obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) of a sample of 29 HerMES DSFGs that have far-infrared (FIR) flux densities that lie between the brightest of sources found by Herschel and fainter DSFGs found via ground-based surveys in the submillimeter region. The ALMA imaging reveals that these DSFGs comprise a total of 62 sources (down to the 5{sigma} point-source sensitivity limit in our ALMA sample; {sigma}~0.2mJy). Optical or near-infrared imaging indicates that 36 of the ALMA sources experience a significant flux boost from gravitational lensing ({mu}>1.1), but only six are strongly lensed and show multiple images. We introduce and make use of uvmcmcfit, a general-purpose and publicly available Markov chain Monte Carlo visibility-plane analysis tool to analyze the source properties. Combined with our previous work on brighter Herschel sources, the lens models presented here tentatively favor intrinsic number counts for DSFGs with a break near 8mJy at 880um and a steep fall-off at higher flux densities. Nearly 70% of the Herschel sources break down into multiple ALMA counterparts, consistent with previous research indicating that the multiplicity rate is high in bright sources discovered in single-dish submillimeter or FIR surveys. The ALMA counterparts to our Herschel targets are located significantly closer to each other than ALMA counterparts to sources found in the LABOCA ECDFS Submillimeter Survey. Theoretical models underpredict the excess number of sources with small separations seen in our ALMA sample. The high multiplicity rate and small projected separations between sources seen in our sample argue in favor of interactions and mergers plausibly driving both the prodigious emission from the brightest DSFGs as well as the sharp downturn above S880=8mJy.
722. ALMA viewing of OH 231.8+4.2
ID:
ivo://CDS.VizieR/J/A+A/618/A164
Title:
ALMA viewing of OH 231.8+4.2
Short Name:
J/A+A/618/A164
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present continuum and molecular line emission ALMA observations of OH 231.8+4.2, a well studied bipolar nebula around an asymptotic giant branch (AGB) star. The high angular resolution (~0.2"-0.3") and sensitivity of our ALMA maps provide the most detailed and accurate description of the overall nebular structure and kinematics of this object to date. We have identified a number of outflow components previously unknown. Species studied in this work include ^12^CO, ^13^CO, CS, SO, SO_2_, OCS, SiO, SiS, H_3_O^+^, Na^37^Cl, and CH_3_OH. The molecules Na^37^Cl and CH_3_OH are first detections in OH 231.8+4.2, with CH_3_OH being also a first detection in an AGB star.
723. ALMA view of G351.77-0.54
ID:
ivo://CDS.VizieR/J/A+A/603/A10
Title:
ALMA view of G351.77-0.54
Short Name:
J/A+A/603/A10
Date:
21 Oct 2021
Publisher:
CDS
Description:
The fragmentation of high-mass gas clumps and the formation of the accompanying accretion disks lie at the heart of high-mass star formation research. We resolve the small-scale structure around the high-mass hot core G351.77-0.54 to investigate its disk and fragmentation properties. Using the Atacama Large Millimeter Array at 690GHz with baselines exceeding 1.5km, we study the dense gas, dust, and outflow emission at an unprecedented spatial resolution of 0.06" (130AU at 2.2kpc). Within the inner few 1000AU, G351.77 is fragmenting into at least four cores (brightness temperatures between 58 and 201K). The central structure around the main submm source #1 with a diameter of ~0.5" does not show additional fragmentation. While the CO(6-5) line wing emission shows an outflow lobe in the northwestern direction emanating from source #1, the dense gas tracer CH_3_CN shows a velocity gradient perpendicular to the outflow that is indicative of rotational motions. Absorption profile measurements against the submm source #2 indicate infall rates on the order of 10^-4^ to 10^-3^M_{sun}_/yr, which can be considered as an upper limit of the mean accretion rates. The position-velocity diagrams are consistent with a central rotating disk-like structure embedded in an infalling envelope, but they may also be influenced by the outflow. Using the CH_3_CN(37k-36k) k-ladder with excitation temperatures up to 1300K, we derive a gas temperature map for source #1 exhibiting temperatures often in excess of 1000K. Brightness temperatures of the submm continuum barely exceed 200K. This discrepancy between gas temperatures and submm dust brightness temperatures (in the optically thick limit) indicates that the dust may trace the disk mid-plane, whereas the gas could trace a hotter gaseous disk surface layer. We conduct a pixel-by-pixel Toomre gravitational stability analysis of the central rotating structure. The derived high Q values throughout the structure confirm that this central region appears stable against gravitational instability. Resolving for the first time a high-mass hot core at 0.06 resolution at submm wavelengths in the dense gas and dust emission allowed us to trace the fragmenting core and the gravitationally stable inner rotating disk-like structure. A temperature analysis reveals hot gas and comparably colder dust that may be attributed to different disk locations traced by dust emission and gas lines. The kinematics of the central structure #1 reveal contributions from a rotating disk, an infalling envelope, and potentially an outflow as well, whereas the spectral profile toward source #2 can be attributed to infall.
724. ALMA view of GMCs in NGC 300
ID:
ivo://CDS.VizieR/J/ApJ/857/19
Title:
ALMA view of GMCs in NGC 300
Short Name:
J/ApJ/857/19
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have conducted a ^12^CO(2-1) survey of several molecular gas complexes in the vicinity of HII regions within the spiral galaxy NGC300 using the Atacama Large Millimeter Array (ALMA). Our observations attain a resolution of 10pc and 1km/s, sufficient to fully resolve giant molecular clouds (GMCs) and the highest obtained to date beyond the Local Group. We use the CPROPS algorithm to identify and characterize 250 GMCs across the observed regions. GMCs in NGC300 appear qualitatively and quantitatively similar to those in the Milky Way disk: they show an identical scaling relationship between size R and linewidth {Delta}V ({Delta}V{propto}R^0.48+/-0.05^), appear to be mostly in virial equilibrium, and are consistent with having a constant surface density of about 60M_{sun}_/pc^2^. The GMC mass spectrum is similar to those in the inner disks of spiral galaxies (including the Milky Way). Our results suggest that global galactic properties such as total stellar mass, morphology, and average metallicity may not play a major role in setting GMC properties, at least within the disks of galaxies on the star-forming main sequence. Instead, GMC properties may be more strongly influenced by local environmental factors such as the midplane disk pressure. In particular, in the inner disk of NGC 300, we find this pressure to be similar to that in the local Milky Way but markedly lower than that in the disk of M51, where GMCs are characterized by systematically higher surface densities and a higher coefficient for the size-linewidth relation.
725. 2A0335+096 LOFAR images
ID:
ivo://CDS.VizieR/J/A+A/659/A20
Title:
2A0335+096 LOFAR images
Short Name:
J/A+A/659/A20
Date:
04 Mar 2022 06:16:07
Publisher:
CDS
Description:
Radio observations represent a powerful probe of the physics occurring in the intracluster medium (ICM) because they trace the relativistic cosmic rays in the cluster magnetic fields, or within galaxies themselves. By probing the low-energy cosmic rays, low-frequency radio observations are especially interesting because they unveil emission powered by low-efficiency particle acceleration processes, which are believed to play a crucial role in the origin of diffuse radio emission. We investigate the origin of the radio mini-halo at the center of the galaxy cluster 2A0335+096 and its connection to the central galaxy and the sloshing cool core. We also study the properties of the head-tail galaxy GB6 B0335+096 hosted in the cluster to explore the lifecycle of the relativistic electrons in its radio tails. We use new LOw Frequency ARray (LOFAR) observations from the LOFAR Two-meter Sky Survey at 144MHz to map the low-frequency emission with a high level of detail. The new data were combined with archival Giant Metrewave Radio Telescope and Chandra observations to carry out a multi-wavelength study. We have made the first measurement of the spectral index of the mini-halo ({alpha}=-1.2+/-0.1 between 144MHz and 1.4GHz) and the lobes of the central source ({alpha}=~-1.5+/-0.1 between 144 and 610MHz). Based on the low-frequency radio emission morphology with respect to the thermal ICM, we propose that the origin of the diffuse radio emission is linked to the sloshing of the cool core. The new data revealed the presence of a Mpc-long radio tail associated with GB6 B0335+096. The observed projected length is a factor 3 longer than the expected cooling length, with evidence of flattening in the spectral index trend along the tail. Therefore, we suggest that the electrons toward the end of the tail are kept alive by the ICM gentle re-acceleration.
726. A low-luminosity type-1 QSO sample. III.
ID:
ivo://CDS.VizieR/J/A+A/580/A113
Title:
A low-luminosity type-1 QSO sample. III.
Short Name:
J/A+A/580/A113
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on the optical spectroscopic analysis of a sample of 99 low-luminosity quasi-stellar objects (LLQSOs) at z<=0.06 base the Hamburg/ESO QSO Survey (HES). To better relate the low-redshift active galactic nucleus (AGN) to the QSO population it is important to study samples of the latter type at a level of detail similar to that of the low-redshift AGN. Powerful QSOs, however, are absent at low redshifts due to evolutionary effects and their small space density. Our understanding of the (distant) QSO population is, therefore, significantly limited by angular resolution and sensitivity. The LLQSOs presented here offer the possibility of studying the faint end of this population at smaller cosmological distances and, therefore, in greater detail. In comparing two spectroscopic methods, we aim to establish a reliable activity classification scheme of the LLQSOs sample. Our goal is to enrich our systematic multiwavelength analysis of the AGN/starburst relation in these systems and give a complementary information on this particular sample of LLQSOs from the Hamburg ESO survey. Here, we present results of the analysis of visible wavelength spectroscopy provided by the HES and the 6 Degree Field Galaxy Survey (6dFGS). These surveys use different spectroscopic techniques, long-slit and circular fiber, respectively. These allow us to assess the influence of different apertures on the activity of the LLQSOs using classical optical diagnostic diagrams. We perform a Gaussian fitting of strong optical emission lines and decompose narrow and broad Balmer components. A small number of our LLQSO present no broad component, which is likely to be present but buried in the noise. Two sources show double broad components, whereas six comply with the classic NLS1 requirements. As expected in NLR of broad line AGNs, the [SII]-based electron density values range between 100 and 1000N_e_/cm^3^. Using the optical characteristics of Populations A and B, we find that 50% of our sources with H{beta} broad emission are consistent with the radio-quiet sources definition. The remaining sources could be interpreted as low-luminosity radio-loud quasar. The BPT-based classification renders an AGN/Seyfert activity between 50 to 60%. For the remaining sources, the possible starburst contribution might control the LINER and HII classification. Finally, we discuss the aperture effect as responsible for the differences found between data sets, although variability in the BLR could play a significant role as well.
727. {alpha}-element abundances in galactic PNe
ID:
ivo://CDS.VizieR/J/ApJ/711/619
Title:
{alpha}-element abundances in galactic PNe
Short Name:
J/ApJ/711/619
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper, we present emission line strengths, abundances, and element ratios (X/O for Ne, S, Cl, and Ar) for a sample of 38 Galactic disk planetary nebulae (PNe) consisting primarily of Peimbert classification Type I. Spectrophotometry for these PNe incorporates an extended optical/near-IR range of 3600-9600{AA} including the [SIII] lines at 9069{AA} and 9532{AA}, setting this relatively large sample apart from typical spectral coverage. We have utilized Emission Line Spectrum Analyzer, a five-level atom abundance routine, to determine Te, Ne, ionization correction factors, and total element abundances, thereby continuing our work toward a uniformly processed set of data. With a compilation of data from >120 Milky Way PNe, we present results from our most recent analysis of abundance patterns in Galactic disk PNe. With a wide range of metallicities, galactocentric distances, and both Type I and non-Type I objects, we have examined the alpha elements against HII regions and blue compact galaxies (H2BCGs) to discern signatures of depletion or enhancement in PNe progenitor stars, particularly the destruction or production of O and Ne.
728. {alpha}-element abundances of Cepheid stars
ID:
ivo://CDS.VizieR/J/A+A/580/A17
Title:
{alpha}-element abundances of Cepheid stars
Short Name:
J/A+A/580/A17
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new homogeneous measurements of Na, Al, and three alpha-elements (Mg, Si, Ca) for 75 Galactic Cepheids, complemented with Cepheid abundances available in the literature, for a total of 439 stars. The abundances are based on high spectral resolution (R~38000) and high signal-to-noise ratio (S/N~50-300) spectra collected with UVES at ESO VLT. Special attention was given to providing a homogeneous abundance scale for these five elements plus iron. In addition, accurate Galactocentric distances (RG) based on near-infrared photometry are also available for all the Cepheids in the sample. We found that these five elements display well-defined linear radial gradients and modest standard deviations over the entire range of RG. The [element/Fe] abundance ratios are constant across the entire thin disk and over the entire period range; only the Ca radial distribution shows marginal evidence of slopes. These results indicate that the chemical enrichment history of iron and of the quoted elements has been quite similar across the four quadrants of the Galactic thin disk, and very homogenous within the range in age covered by the Cepheids (~10-300Myr). Finally, we also find that Cepheid abundances agree with similar abundances for thin and thick disk dwarf stars, and they follow the typical Mg-Al and Na-O correlations.
729. alpha-enhanced integrated Lick/IDS spectral indices
ID:
ivo://CDS.VizieR/J/ApJS/160/176
Title:
alpha-enhanced integrated Lick/IDS spectral indices
Short Name:
J/ApJS/160/176
Date:
21 Oct 2021
Publisher:
CDS
Description:
All 25 Lick/IDS spectral indices have been computed for the integrated light of simple stellar populations over broad ranges of age and metallicity and with effects from horizontal-branch stars fully implemented. Our models employ {alpha}-enhanced isochrones at the sub-solar metallicity regime, but solar-scaled ones at solar and super-solar metallicity. We have also employed the updated response functions of Houdashelt et al. (2002AAS...201.1405H) at the solar and super-solar metallicity regime, so that we could assess the light-element enhancement phenomena seen from metal-rich early-type galaxies.
730. alpha & Fe abundances in the giant stellar stream
ID:
ivo://CDS.VizieR/J/ApJ/883/128
Title:
alpha & Fe abundances in the giant stellar stream
Short Name:
J/ApJ/883/128
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first measurements of [Fe/H] and [{alpha}/Fe] abundances, obtained using spectral synthesis modeling, for red giant branch stars in M31's giant stellar stream (GSS). The spectroscopic observations, obtained at a projected distance of 17kpc from M31's center, yielded 61 stars with [Fe/H] measurements, including 21 stars with [{alpha}/Fe] measurements, from 112 targets identified as M31 stars. The [Fe/H] measurements confirm the expectation from photometric metallicity estimates that stars in this region of M31's halo are relatively metal rich compared to stars in the Milky Way's inner halo: more than half the stars in the field, including those not associated with kinematically identified substructure, have [Fe/H] abundances >-1.0. The stars in this field are {alpha}-enhanced at lower metallicities, while [{alpha}/Fe] decreases with increasing [Fe/H] above metallicities of [Fe/H]>~-0.9. Three kinematical components have been previously identified in this field: the GSS, a second kinematically cold feature of unknown origin, and M31's kinematically hot halo. We compare probabilistic [Fe/H] and [{alpha}/Fe] distribution functions for each of the components. The GSS and the second kinematically cold feature have very similar abundance distributions, while the halo component is more metal poor. Although the current sample sizes are small, a comparison of the abundances of stars in the GSS field with abundances of M31 halo and dSph stars from the literature indicate that the progenitor of the stream was likely more massive, and experienced a higher efficiency of star formation, than M31's existing dSphs or the dEs NGC147 and NGC185.

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