- ID:
- ivo://CDS.VizieR/J/MNRAS/452/637
- Title:
- Distance-limited sample of MYSOs
- Short Name:
- J/MNRAS/452/637
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse C^18^O (J=3-2) data from a sample of 99 infrared (IR)-bright massive young stellar objects (MYSOs) and compact HII regions that were identified as potential molecular-outflow sources in the Red MSX Source survey. We extract a distance-limited (D<6kpc) sample shown to be representative of star formation covering the transition between the source types. At the spatial resolution probed, Larson-like relationships are found for these cores, though the alternative explanation, that Larson's relations arise where surface-density-limited samples are considered, is also consistent with our data. There are no significant differences found between source properties for the MYSOs and HII regions, suggesting that the core properties are established prior to the formation of massive stars, which subsequently have little impact at the later evolutionary stages investigated. There is a strong correlation between dust-continuum and C^18^O-gas masses, supporting the interpretation that both trace the same material in these IR-bright sources. A clear linear relationship is seen between the independently established core masses and luminosities. The position of MYSOs and compact HII regions in the mass-luminosity plane is consistent with the luminosity expected from the most massive protostar in the cluster when using an ~40 percent star formation efficiency and indicates that they are at a similar evolutionary stage, near the end of the accretion phase.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/487/2061
- Title:
- Distances for 2062 nearby spiral galaxies
- Short Name:
- J/MNRAS/487/2061
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the final distance measurements for the 2MASS Tully-Fisher (2MTF) survey. The final 2MTF catalogue contains 2062 nearby spiral galaxies in the CMB frame velocity range of 600<cz<10000km/s with a mean velocity of 4805km/s. The main update in this release is the replacement of some archival HI data with newer ALFALFA data. Using the 2MTF template relation, we calculate the distances and peculiar velocities of all 2MTF galaxies. The mean uncertainties of the linear distance measurements are around 22 per cent in all three infrared bands. 2MTF measurements agree well with the distances from the Cosmicflows-3 compilation, which contains 1117 common galaxies, including 28 with SNIa distance measurements. Using distances estimated from the '3-bands combined' 2MTF sample and a {chi}^2^ minimization method, we find best-fitting bulk flow amplitudes of 308+/-26km/s, 318+/-29km/s, and 286+/-25km/s at depths of R_I_=20, 30 and 40h^-1^Mpc, respectively, which is consistent with the {LAMNDA}CDM model and with previous 2MTF results with different estimation techniques and a preliminary catalogue.
- ID:
- ivo://CDS.VizieR/J/AJ/115/1989
- Title:
- Distances of galactic planetary nebulae
- Short Name:
- J/AJ/115/1989
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is well known that the IRAS colors of planetary nebulae (PNe) are very similar to blackbody colors. Taking account of this characteristic, we define a new method to obtain some information about the distance to PNe by blackbody fitting of IRAS four-band fluxes, assuming these fluxes are due to thermal emission from the nebular dust envelope. The fit should have two free parameters - the dust temperature TD and the distance-dependent "scaling factor" A - under the assumption of uniform dust mass. We find that the A-values have a good correlation with published distances. The scaling factor A could be a more effective distance scale than others, because many PNe have been detected as IRAS sources and the extinction of IRAS fluxes is not so severe, and is known. We also find that TD is concentrated between 100 and 200K, with a typical value of about 150K.
- ID:
- ivo://CDS.VizieR/J/ApJ/838/107
- Title:
- Distances to RRab stars from WISE and Gaia
- Short Name:
- J/ApJ/838/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Pulsating stars, such as Cepheids, Miras, and RR Lyrae stars, are important distance indicators and calibrators of the "cosmic distance ladder," and yet their period-luminosity-metallicity (PLZ) relations are still constrained using simple statistical methods that cannot take full advantage of available data. To enable optimal usage of data provided by the Gaia mission, we present a probabilistic approach that simultaneously constrains parameters of PLZ relations and uncertainties in Gaia parallax measurements. We demonstrate this approach by constraining PLZ relations of type ab RR Lyrae stars in near-infrared W1 and W2 bands, using Tycho-Gaia Astrometric Solution (TGAS) parallax measurements for a sample of ~100 type ab RR Lyrae stars located within 2.5kpc of the Sun. The fitted PLZ relations are consistent with previous studies, and in combination with other data, deliver distances precise to 6% (once various sources of uncertainty are taken into account). To a precision of 0.05mas (1{sigma}), we do not find a statistically significant offset in TGAS parallaxes for this sample of distant RR Lyrae stars (median parallax of 0.8mas and distance of 1.4kpc). With only minor modifications, our probabilistic approach can be used to constrain PLZ relations of other pulsating stars, and we intend to apply it to Cepheid and Mira stars in the near future.
- ID:
- ivo://CDS.VizieR/J/A+A/580/A68
- Title:
- 3D observations of S 140
- Short Name:
- J/A+A/580/A68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The objective of this work is to study in detail the temperatures of dust and gas in the photon-dominated region S140, especially around the deeply embedded infrared sources IRS1-3 and at the ionization front. We derive the dust temperature and column density by combining Herschel PACS continuum observations with SOFIA observations at 37um and SCUBA data at 450um. We model these observations using simple greybody fits and the DUSTY radiative transfer code. For the gas analysis we use RADEX to model the CO 1-0, CO 2-1, ^13^CO 1-0 and C^18^O 1-0 emission lines mapped with the IRAM-30m telescope over a 4' field. Around IRS 1-3, we use HIFI observations of single-points and cuts in CO 9-8, ^13^CO 10-9 and C^18^O 9-8 to constrain the amount of warm gas
196. DRaGONS survey
- ID:
- ivo://CDS.VizieR/J/ApJ/649/63
- Title:
- DRaGONS survey
- Short Name:
- J/ApJ/649/63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results from the Distant Radio Galaxies Optically Non-detected in the SDSS (DRaGONS) survey. Using a novel selection technique for identifying high-redshift radio galaxy (HzRG) candidates, a large sample is compiled using bright (S_1.4GHz_>100mJy) radio sources from the FIRST survey having no optical counterpart in the SDSS. Near-IR K-band imaging for 96 targets allows preliminary identification of HzRG candidates through the well-known K-z relation, for subsequent spectroscopic observation. We measure magnitudes brighter than K~19.5 for 70 of the 96, and limiting magnitudes for the remainder. Redshifts based on a linear fit to the K-z diagram give a mean <z>=2.5 and median z=2.0, showing that this method should be efficient at identifying a large number of HzRGs.
- ID:
- ivo://CDS.VizieR/J/ApJ/790/124
- Title:
- Dust and gas physics of the GOALS sample
- Short Name:
- J/ApJ/790/124
- Date:
- 13 Dec 2021 06:47:30
- Publisher:
- CDS
- Description:
- The Great Observatories All-sky LIRG Survey (GOALS) is a comprehensive, multiwavelength study of luminous infrared galaxies (LIRGs) in the local universe. Here, we present the results of a multi-component, spectral decomposition analysis of the low-resolution mid-infrared (MIR) Spitzer Infrared Spectrograph spectra from 5-38 {mu}m of 244 LIRG nuclei. The detailed fits and high-quality spectra allow for characterization of the individual polycyclic aromatic hydrocarbon (PAH) features, warm molecular hydrogen emission, and optical depths for both silicate dust grains and water ices. We find that starbursting LIRGs, which make up the majority of the GOALS sample, are very consistent in their MIR properties (i.e., {tau}_9.7 {mu}m_, {tau}_ice_, neon line ratios, and PAH feature ratios). However, as their EQW_6.2 {mu}m_decreases, usually an indicator of an increasingly dominant active galactic nucleus (AGN), LIRGs cover a larger spread in these MIR parameters. The contribution from PAH emission to the total IR luminosity (L(PAH)/L(IR)) in LIRGs varies from 2%-29% and LIRGs prior to their first encounter show significantly higher L(PAH)/L(IR) ratios on average. We observe a correlation between the strength of the starburst (represented by IR8 = L_IR_/L_8 {mu}m_) and the PAH fraction at 8 {mu}m but no obvious link between IR8 and the 7.7 to 11.3 PAH ratio, suggesting that the fractional photodissociation region (PDR) emission, and not the overall grain properties, is associated with the rise in IR8 for galaxies off the starburst main sequence. We detect crystalline silicate features in ~6% of the sample but only in the most obscure sources (s_9.7 {mu}m_< -1.24). Ice absorption features are observed in ~11% (56%) of GOALS LIRGs (ULIRGs) in sources with a range of silicate depths. Most GOALS LIRGs have L(H_2_)/L(PAH) ratios elevated above those observed for normal star-forming galaxies and exhibit a trend for increasing L(H_2_)/L(PAH) ratio with increasing L(H_2_). While star formation appears to be the dominant process responsible for exciting the H_2_ in most of the GOALS galaxies, a subset of LIRGs (~10%) shows excess H_2_emission that is inconsistent with PDR models and may be excited by shocks or AGN-induced outflows.
- ID:
- ivo://CDS.VizieR/J/ApJ/753/172
- Title:
- Dust classification in Galactic PNe
- Short Name:
- J/ApJ/753/172
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Spitzer/Infrared Spectrograph (IRS) spectra of 157 compact Galactic planetary nebulae (PNe). These young PNe provide insight on the effects of dust in early post-asymptotic giant branch evolution, before much of the dust is altered or destroyed by the hardening stellar radiation field. Most of the selected targets have PN-type IRS spectra, while a few turned out to be misclassified stars. We inspected the group properties of the PN spectra and classified them based on the different dust classes (featureless or F, carbon-rich dust or CRD, oxygen-rich dust or ORD, mixed-chemistry dust or MCD) and subclasses (aromatic and aliphatic, and crystalline and amorphous). All PNe are characterized by dust continuum and more than 80% of the sample shows solid-state features above the continuum, in contrast with the Magellanic Cloud sample where only ~40% of the entire sample displays solid-state features; this is an indication of the strong link between dust properties and metallicity.
- ID:
- ivo://CDS.VizieR/J/A+A/447/221
- Title:
- Dust continuum emission from IRAS sources
- Short Name:
- J/A+A/447/221
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In an ongoing effort to identify and study high-mass protostellar candidates we have observed in various tracers a sample of 235 sources selected from the IRAS Point Source Catalog (Cat. <II/125>), mostly with delta<-30{deg}, with the SEST antenna at millimeter wavelengths. The sample contains 142 Low sources and 93 High, which are believed to be in different evolutionary stages. Both sub-samples have been studied in detail by comparing their physical properties and morphologies.
- ID:
- ivo://CDS.VizieR/J/ApJ/697/182
- Title:
- Dust emission from unobscured AGN
- Short Name:
- J/ApJ/697/182
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use mid-infrared (MIR) spectroscopy of unobscured active galactic nuclei (AGNs) to reveal their native dusty environments. We concentrate on Seyfert 1 galaxies, observing a sample of 31 with the Infrared Spectrograph aboard the Spitzer Space Telescope, and compare them with 21 higher luminosity quasar counterparts.
