- ID:
- ivo://CDS.VizieR/J/A+A/569/L1
- Title:
- Polarization hole in a starless core
- Short Name:
- J/A+A/569/L1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to investigate the polarization properties of a starless core in a very early evolutionary stage. Linear polarization data reveal the properties of the dust grains in the distinct phases of the interstellar medium. Our goal is to investigate how the polarization degree and angle correlate with the cloud and core gas. We use optical, near infrared and submillimeter polarization observations toward the starless object Pipe-109 in the Pipe nebula. Our data cover a physical scale range of 0.08 to 0.4pc, comprising the dense gas, envelope and the surrounding cloud. The cloud polarization is well traced by the optical data. The near infrared polarization is produced by a mixed population of grains from the core border and the cloud gas. The optical and near infrared polarization toward the cloud reach the maximum possible value and saturate with respect to the visual extinction. The core polarization is predominantly traced by the submillimeter data and have a steep decrease with respect to the visual extinction. Modeling of the submillimeter polarization indicates a magnetic field main direction projected onto the plane-of-sky and loss of grain alignment for densities higher than 6x10^4^cm^-3^ (or A_V_>30mag). Pipe-109 is immersed in a magnetized medium, with a very ordered magnetic field. The absence of internal source of radiation significantly affects the polarization efficiencies in the core, creating a polarization hole at the center of the starless core. This result supports the theory of dust grain alignment via radiative torques.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/765/9
- Title:
- Predicted CO and [CII] fluxes of HUDF galaxies
- Short Name:
- J/ApJ/765/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Modern (sub-)millimeter/radio interferometers such as ALMA, JVLA, and the PdBI successor NOEMA will enable us to measure the dust and molecular gas emission from galaxies that have luminosities lower than the Milky Way, out to high redshifts and with unprecedented spatial resolution and sensitivity. This will provide new constraints on the star formation properties and gas reservoir in galaxies throughout cosmic times through dedicated deep field campaigns targeting the CO/[C II] lines and dust continuum emission in the (sub-)millimeter regime. In this paper, we present empirical predictions for such line and continuum deep fields. We base these predictions on the deepest available optical/near-infrared Advanced Camera for Surveys and NICMOS data on the Hubble Ultra Deep Field (over an area of about 12arcmin^2^). Using a physically motivated spectral energy distribution model, we fit the observed optical/near-infrared emission of 13099 galaxies with redshifts up to z=5, and obtain median-likelihood estimates of their stellar mass, star formation rate, dust attenuation, and dust luminosity. We combine the attenuated stellar spectra with a library of infrared emission models spanning a wide range of dust temperatures to derive statistical constraints on the dust emission in the infrared and (sub-)millimeter which are consistent with the observed optical/near-infrared emission in terms of energy balance. This allows us to estimate, for each galaxy, the (sub-)millimeter continuum flux densities in several ALMA, PdBI/NOEMA, and JVLA bands. As a consistency check, we verify that the 850{mu}m number counts and extragalactic background light derived using our predictions are consistent with previous observations. Using empirical relations between the observed CO/[C II] line luminosities and the infrared luminosity of star-forming galaxies, we infer the luminosity of the CO(1-0) and [C II] lines from the estimated infrared luminosity of each galaxy in our sample.
- ID:
- ivo://CDS.VizieR/J/A+A/534/A118
- Title:
- Predicted dust emissivity in 100-10000um bands
- Short Name:
- J/A+A/534/A118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a previous paper we proposed a new model for the emission by amorphous astronomical dust grains, based on solid-state physics. The model uses a description of the disordered charge distribution (DCD) combined with the presence of two-level systems (TLS) defects in the amorphous solid composing the grains. The goal of this paper is to compare this new model to astronomical observations of different Galactic environments in the far-infrared/ submillimeter, in order to derive a set of canonical model parameters to be used as a Galactic reference to be compared to in future Galactic and extragalactic studies. We compare the TLSmodel with existing astronomical data. We consider the average emission spectrum at high latitudes in our Galaxy as measured with FIRAS and WMAP, as well as the emission from Galactic compact sources observed with the Archeops balloon experiment, for which an inverse relationship between the dust temperature and the emissivity spectral index has been proven.
- ID:
- ivo://CDS.VizieR/J/ApJ/684/1240
- Title:
- Prestellar cores in Perseus, Serpens and Ophiuchus
- Short Name:
- J/ApJ/684/1240
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an unbiased census of starless cores in Perseus, Serpens, and Ophiuchus, assembled by comparing large-scale Bolocam 1.1mm continuum emission maps with Spitzer c2d surveys. We use the c2d catalogs to separate 108 starless from 92 protostellar cores in the 1.1mm core samples from Enoch and Young and their coworkers. A comparison of these populations reveals the initial conditions of the starless cores.
- ID:
- ivo://CDS.VizieR/J/A+A/588/A30
- Title:
- Properties of cores in OMC 2/3
- Short Name:
- J/A+A/588/A30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new measurements of the dust emissivity index, {beta}, for the high-mass, star-forming OMC 2/3 filament. We combined 160-500um data from Herschel with long-wavelength observations at 2mm and fit the spectral energy distributions across a=~2pc long, continuous section of OMC 2/3 at 15000AU (0.08pc) resolution. With these data, we measured {beta} and reconstructed simultaneously the filtered-out large-scale emission at 2mm. We implemented both variable and fixed values of {beta}, finding that {beta}=1.7-1.8 provides the best fit across most of OMC 2/3. These {beta} values are consistent with a similar analysis carried out with filtered Herschel data. Thus, we show that {beta} values derived from spatial filtered emission maps agree well with those values from unfiltered data at the same resolution. Our results contradict the very low {beta} values (~0.9) previously measured in OMC 2/3 between 1.2mm and 3.3mm data, which we attribute to elevated fluxes in the 3.3mm observations. Therefore, we find no evidence of rapid, extensive dust grain growth in OMC 2/3. Future studies with Herschel data and complementary ground-based long-wavelength data can apply our technique to obtain reliable determinations of {beta} in nearby cold molecular clouds.
- ID:
- ivo://CDS.VizieR/J/MNRAS/402/603
- Title:
- Properties of SCUBA cores in Perseus mol. cloud
- Short Name:
- J/MNRAS/402/603
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new analysis of the properties of star-forming cores in the Perseus molecular cloud, identified in SCUBA 850um data originally presented by Hatchell et al. (2005, Cat. J/A+A/440/151). Our goal is to determine which core properties can be robustly identified and which depend on the extraction technique. Four regions in the cloud are examined: NGC 1333, IC348/HH211, L1448 and L1455. We identify clumps of dust emission using two popular automated algorithms, clfind and gaussclumps, finding 85 and 122 clumps in total, respectively. Using the catalogues of Hatchell et al. (2005, Cat. J/A+A/440/151), we separate these clumps into starless, Class 0 and Class I cores.
- ID:
- ivo://CDS.VizieR/J/ApJ/797/138
- Title:
- Properties of SMG lens candidates
- Short Name:
- J/ApJ/797/138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Keck-Adaptive Optics and Hubble Space Telescope high resolution near-infrared (IR) imaging for 500{mu}m bright candidate lensing systems identified by the Herschel Multi-tiered Extragalactic Survey and Herschel Astrophysical Terahertz Large Area Survey. Out of 87 candidates with near-IR imaging, 15 (~17%) display clear near-IR lensing morphologies. We present near-IR lens models to reconstruct and recover basic rest-frame optical morphological properties of the background galaxies from 12 new systems. Sources with the largest near-IR magnification factors also tend to be the most compact, consistent with the size bias predicted from simulations and previous lensing models for submillimeter galaxies (SMGs). The rest-frame optical properties of our sample of Herschel-selected lensed SMGs are consistent with those of unlensed SMGs, which suggests that the two populations are similar.
- ID:
- ivo://CDS.VizieR/J/MNRAS/468/4006
- Title:
- Proto-cluster candidate fields
- Short Name:
- J/MNRAS/468/4006
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present SCUBA-2 follow-up of 61 candidate high-redshift Planck sources. Of these, 10 are confirmed strong gravitational lenses and comprise some of the brightest such submm sources on the observed sky, while 51 are candidate proto-cluster fields undergoing massive starburst events. With the accompanying Herschel-Spectral and Photometric Imaging Receiver observations and assuming an empirical dust temperature prior of 34^+13^_-9_K, we provide photometric redshift and far-IR luminosity estimates for 172 SCUBA-2-selected sources within these Planck overdensity fields. The redshift distribution of the sources peak between a redshift of 2 and 4, with one-third of the sources having S_500_/S_350_>1. For the majority of the sources, we find far-IR luminosities of approximately 10^13^L_{sun}_, corresponding to star formation rates of around 1000M_{sun}_/yr. For S_850_>8mJy sources, we show that there is up to an order of magnitude increase in star formation rate density and an increase in uncorrected number counts of 6 for S_850_>8mJy when compared to typical cosmological survey fields. The sources detected with SCUBA-2 account for only approximately 5 per cent of the Planck flux at 353 GHz, and thus many more fainter sources are expected in these fields.
- ID:
- ivo://CDS.VizieR/J/A+A/640/A27
- Title:
- Protoplanetary disk masses in NGC 2024
- Short Name:
- J/A+A/640/A27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Protoplanetary disks in dense, massive star-forming regions (SFRs) are strongly affected by their environment. How this environmental impact changes over time is an important constraint on disk evolution and external photoevaporation models. We characterized the dust emission from 179 disks in the core of the young (0.5Myr) NGC 2024 cluster. By studying how the disk mass varies within the cluster, and comparing these disks to those in other regions, we determined how external photoevaporation influences disk properties over time. Using the Atacama Large Millimeter/submillimeter Array (ALMA), a 2.9'x2.9' mosaic centered on NGC 2024 FIR 3 was observed at 225GHz with a resolution of 0.25'', or ~100AU. It contains 179 disks identified at IR wavelengths, 7 new disk candidates, and several protostars. Of the disks in the sample, 57 are detected. The overall detection rate is 32+/-4%. Few of the disks are resolved, with the exception of a giant (R=300AU) transition disk. Serendipitously, we observe a millimeter flare from an X-ray bright Young Stellar Object (YSO), and resolve continuum emission from a Class 0 YSO in the FIR 3 core. Two distinct disk populations are present: a more massive one in the east, along the dense molecular ridge hosting the FIR 1-5 YSOs, with a detection rate of 45+/-7%. In the western population, towards IRS 1, only 15+/-4% of disks are detected. NGC 2024 hosts two distinct disk populations. Disks along the dense molecular ridge are young (0.2-0.5Myr) and partly shielded from the FUV radiation of IRS 2b; their masses are similar to isolated 1-3Myr old SFRs. The western population is older and at lower extinctions, and may be affected by external photoevaporation from both IRS 1 and IRS 2b. It is, however, possible these disks had lower masses to begin with.
- ID:
- ivo://CDS.VizieR/J/ApJ/802/77
- Title:
- Protoplanetary disk masses in NGC 2024 cluster
- Short Name:
- J/ApJ/802/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from a Submillimeter Array survey of the 887{mu}m continuum emission from the protoplanetary disks around 95 young stars in the young cluster NGC 2024. Emission was detected from 22 infrared sources, with flux densities from ~5 to 330mJy; upper limits (at 3{sigma}) for the other 73 sources range from 3 to 24mJy. For standard assumptions, the corresponding disk masses range from ~0.003 to 0.2M_{sun}_, with upper limits at 0.002-0.01M_{sun}_. The NGC 2024 sample has a slightly more populated tail at the high end of its disk mass distribution compared to other clusters, but without more information on the nature of the sample hosts it remains unclear if this difference is statistically significant or a superficial selection effect. Unlike in the Orion Trapezium, there is no evidence for a disk mass dependence on the (projected) separation from the massive star IRS 2b in the NGC 2024 cluster. We suggest that this is due to either the cluster youth or a comparatively weaker photoionizing radiation field.
