- ID:
- ivo://CDS.VizieR/J/MNRAS/363/405
- Title:
- SIMBA observations of cold cores
- Short Name:
- J/MNRAS/363/405
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a 1.2-mm continuum emission survey toward 131 star-forming complexes suspected of undergoing massive star formation. These regions have previously been identified as harbouring a methanol maser and/or a radio continuum source [ultracompact (UC) HII region], the presence of which is in most instances indicative of massive star formation. The 1.2-mm emission was mapped using the SIMBA instrument on the 15-m Swedish ESO Submillimetre Telescope (SEST). Emission is detected toward all of the methanol maser and UC HII regions targeted, as well as towards 20 others lying within the fields mapped, implying that these objects are associated with cold, deeply embedded objects. Interestingly, there are also 20 methanol maser sites and nine UC HII regions within the fields mapped which are devoid of millimetre continuum emission. In addition to the maser and UC HII regions detected, we have also identified 253 other sources within the SIMBA maps. All of these (253) are new sources, detected solely from their millimetre continuum emission. In total, 404 sources are detected, representing four classes of sources which are distinguished by the presence of the different combination of associated tracers.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/586/A149
- Title:
- SiO in ATLASGAL-selected massive clumps
- Short Name:
- J/A+A/586/A149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The processes leading to the birth of high-mass stars are poorly understood. The key first step to reveal their formation processes is characterising the clumps and cores from which they form. We define a representative sample of massive clumps in different evolutionary stages selected from the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL), from which we aim to establish a census of molecular tracers of their evolution. As a first step, we study the shock tracer, SiO, mainly associated with shocks from jets probing accretion processes. In low-mass young stellar objects (YSOs), outflow and jet activity decreases with time during the star formation processes. Recently, a similar scenario was suggested for massive clumps based on SiO observations. Here we analyse observations of the SiO (2-1) and (5-4) lines in a statistically significant sample to constrain the change of SiO abundance and the excitation conditions as a function of evolutionary stage of massive star-forming clumps. We performed an unbiased spectral line survey covering the 3-mm atmospheric window between 84-117GHz with the IRAM 30m telescope of a sample of 430 sources of the ATLASGAL survey, covering various evolutionary stages of massive clumps. A smaller sample of 128 clumps has been observed in the SiO (5-4) transition with the APEX telescope to complement the (2-1) line and probe the excitation conditions of the emitting gas. We derived detection rates to assess the star formation activity of the sample, and we estimated the column density and abundance using both an LTE approximation and non-LTE calculations for a smaller subsample, where both transitions have been observed.
- ID:
- ivo://CDS.VizieR/J/ApJS/165/360
- Title:
- SiO maser emission toward 10 late-type stars
- Short Name:
- J/ApJS/165/360
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of simultaneous time monitoring observations of SiO J=2-1 and J=3-2 maser emission for 10 late-type stars (8 Mira variables, 1 OH/IR star, and 1 supergiant) with the 14m radio telescope at Taeduk Radio Astronomy Observatory from 1999 January to 2001 February. The SiO v=1, J=2-1 and J=3-2 maser emission was detected at almost all observational epochs. The SiO v=2, J=2-1 maser was detected from 4 late-type stars (VY CMa, R Cas, Cyg, R Leo) and the v=2, J=3-2 maser was detected from 7 stars (R Aqr, TX Cam, R Cas, Cyg, W Hya, R Leo, IK Tau). The v=3, J=2-1 and masers were also detected from Cyg and TX Cam, respectively. Based on these observational data, line profile and peak velocity variations with respect to stellar velocity, antenna temperatures, and their ratio variations as a function of optical phase of central star were investigated. Description:
- ID:
- ivo://CDS.VizieR/J/ApJ/821/125
- Title:
- SMA obs. of giant molecular clouds in NGC 300
- Short Name:
- J/ApJ/821/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first high angular resolution study of giant molecular clouds (GMCs) in the nearby spiral galaxy NGC 300, based on observations from the Submillimeter Array (SMA). We target eleven 500pc sized regions of active star formation within the galaxy in the ^12^CO(J=2-1) line at 40pc spatial and 1km/s spectral resolution and identify 45 individual GMCs. We characterize the physical properties of these GMCs, and find that they are similar to GMCs in the disks of the Milky Way and other nearby spiral galaxies. For example, the GMC mass spectrum in our sample has a slope of 1.80+/-0.07. Twelve clouds are spatially resolved by our observations, of which ten have virial mass estimates that agree to within a factor of two with mass estimates derived directly from ^12^CO integrated intensity, suggesting that the majority of these GMCs are bound. The resolved clouds show consistency with Larson's fundamental relations between size, linewidth, and mass observed in the Milky Way. We find that the linewidth scales with the size as {Delta}V{propto}R^0.52+/-0.20^, and the median surface density in the subsample is 54M_{sun}_/pc^2^. We detect ^13^CO in four GMCs and find a mean ^12^CO/^13^CO flux ratio of 6.2. Our interferometric observations recover between 30% and 100% of the integrated intensity from the APEX single dish ^12^CO observations of Faesi et al. (2014, J/ApJ/789/81), suggesting the presence of low-mass GMCs and/or diffuse gas below our sensitivity limit. The fraction of APEX emission recovered increases with the SMA total intensity, as well as with the star formation rate.
- ID:
- ivo://CDS.VizieR/J/A+A/541/L1
- Title:
- SN 1987A images at 350 and 870um
- Short Name:
- J/A+A/541/L1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Supernova 1987A (SN 1987A) in the neighbouring Large Magellanic Cloud offers a superb opportunity to follow the evolution of a supernova and its remnant in unprecedented detail. Recently, far-infrared (far-IR) and sub-mm emission was detected from the direction of SN 1987A, which was interpreted as due to the emission from dust, possibly freshly synthesized in the SN ejecta. To better constrain the location and hence origin of the far-IR and sub-mm emission in SN 1987A, we have attempted to resolve the object in that part of the electro-magnetic spectrum.
- ID:
- ivo://CDS.VizieR/J/A+A/580/A51
- Title:
- SNR G18.8+0.3 data cubes
- Short Name:
- J/A+A/580/A51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a previous paper we investigated the molecular environment toward the eastern border of the supernova remnant (SNR) G18.8+0.3. Continuing with the study of the surroundings of this SNR, we now focus on its southern border, which in the radio continuum emission shows a very peculiar morphology with a corrugated corner and a very flattened southern flank. We observed two regions toward the south of SNR G18.8+0.3 using the Atacama Submillimeter Telescope Experiment (ASTE) in the ^12^CO J=3-2. One of these regions was also surveyed in ^13^ CO and C^18^O J=3-2. The angular and spectral resolution of these observations were 22" and 0.11km/s. We compared the CO emission to 20cm radio continuum maps obtained as part of the Multi-Array Galactic Plane Imaging Survey (MAGPIS) and 870um dust emission extracted from the APEX Telescope Large Area Survey of the Galaxy.
- ID:
- ivo://CDS.VizieR/J/ApJ/659/84
- Title:
- Spectroscopy and photometry of z~=5 galaxies
- Short Name:
- J/ApJ/659/84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new measurement of the integrated stellar mass per comoving volume at redshift 5 determined via spectral energy fitting drawn from a sample of 214 photometrically selected galaxies with z'_850LP_<26.5 in the southern GOODS field. Following recent procedures introduced by Eyles et al. (2007MNRAS.374..910E), we estimate stellar masses for various subsamples for which reliable and unconfused Spitzer IRAC detections are available. A spectroscopic sample of 14 of the most luminous sources with z{bar}=4.92 provides a firm lower limit to the stellar mass density of 1x10^6^M_{sun}_/Mpc^3^. We then consider a larger sample whose photometric redshifts in the publicly available GOODS-MUSIC catalog lie in the range 4.4<z<5.6.
- ID:
- ivo://CDS.VizieR/J/ApJ/761/140
- Title:
- Spectroscopy of Herschel-SPIRE galaxies
- Short Name:
- J/ApJ/761/140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Keck spectroscopic observations and redshifts for a sample of 767 Herschel-SPIRE selected galaxies (HSGs) at 250, 350, and 500{mu}m, taken with the Keck I Low Resolution Imaging Spectrometer and the Keck II DEep Imaging Multi-Object Spectrograph. The redshift distribution of these SPIRE sources from the Herschel Multitiered Extragalactic Survey (HerMES) peaks at z=0.85, with 731 sources at z<2 and a tail of sources out to z~5. We measure more significant disagreement between photometric and spectroscopic redshifts (<{Delta}z/(1+z_spec_)>=0.29) than is seen in non-infrared selected samples, likely due to enhanced star formation rates and dust obscuration in infrared-selected galaxies. The infrared data are used to directly measure integrated infrared luminosities and dust temperatures independent of radio or 24{mu}m flux densities. By probing the dust spectral energy distribution (SED) at its peak, we estimate that the vast majority (72%-83%) of z<2 Herschel-selected galaxies would drop out of traditional submillimeter surveys at 0.85-1mm. This work significantly increased the number of spectroscopically confirmed infrared-luminous galaxies at z{Gt}0 and demonstrates the growing importance of dusty starbursts for galaxy evolution studies and the build-up of stellar mass throughout cosmic time.
- ID:
- ivo://CDS.VizieR/J/A+A/628/A68
- Title:
- SPHERE image of RY Tau
- Short Name:
- J/A+A/628/A68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Jets are rarely associated with pre-main-sequence intermediate-mass stars. This contrasts with the frequent detection of jets in lower-mass or younger stars. Optical and near-IR observations of jet-driving sources are often hindered by the presence of a natal envelope. Jets around partly embedded sources are a useful diagnostic to constrain the geometry of the concealed protoplanetary disk. In fact, the jet-driving mechanisms are affected by both spatial anisotropies and episodic variations at the (sub-)au scale from the star. We obtained a rich set of high-contrast VLT/SPHERE observations from 0.6um to 2.2um of the young intermediate-mass star RY Tau. Given the proximity to the Sun of this source, our images have the highest spatial resolution ever obtained for an atomic jet (down to 4au). Optical observations in polarized light show no sign of the protoplanetary disk detected by ALMA. Instead, we observed a diffuse signal resembling a remnant envelope with an outflow cavity. The jet is detected in the H{alpha}, [SII] at 1.03um, HeI at 1.08um, and [FeII] lines in the 1.25um and 1.64um. The jet appears to be wiggling and its radial width increasing with the distance is complementary to the shape of the outflow cavity suggesting a strong jet/envelope interaction. Through the estimated tangential velocity (~100km/s), we revealed a possible connection between the launching time of the jet sub-structures and the stellar activity of RY Tau. RY Tau is at an intermediate stage toward the dispersal of the natal envelope. This source shows episodic increases of mass accretion /ejection similarly to other known intermediate-mass stars. The amount of observed jet wiggle is consistent with the presence of a precessing disk warp or misaligned inner disk that would be induced by an unseen planetary/sub-stellar companion at sub-/few-au scales. The high disk mass of RY Tau and of two other jet-driving intermediate-mass stars, HD163296 and MWC480, suggests that massive, full disks are more efficient at launching prominent jets.
- ID:
- ivo://CDS.VizieR/J/A+A/570/A55
- Title:
- Spiderweb galaxy 870um and 1.4GHz images
- Short Name:
- J/A+A/570/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present APEX LABOCA 870{mu}m observations of the field around the high-redshift radio galaxy MRC1138-262 at z=2.16. We detect 16 submillimeter galaxies (SMGs) in this ~140-arcmin^2^ bolometer map with flux densities in the range 3-11mJy. The raw number counts indicate a density of SMGs that is up to four times that of blank field surveys. Based on an exquisite multiwavelength database, including VLA 1.4 GHz radio and infrared observations, we investigate whether these sources are members of the protocluster structure at z=~2.2. Using Herschel PACS and SPIRE and Spitzer MIPS photometry, we derive reliable far-infrared (FIR) photometric redshifts for all sources. Follow-up VLT ISAAC and SINFONI NIR spectra confirm that four of these SMGs have redshifts of z=~2.2. We also present evidence that another SMG in this field, detected earlier at 850{mu}m, has a counterpart that exhibits H{alpha} and CO(1-0) emission at z=2.15. Including the radio galaxy and two SMGs with FIR photometric redshifts at z=2.2, we conclude that at least eight submm sources are part of the protocluster at z=2.16 associated with the radio galaxy MRC1138-262. We measure a star formation rate density SFRD~1500M_{sun}_/yr/Mpc^3^, four magnitudes higher than the global SFRD of blank fields at this redshift. Strikingly, these eight sources are concentrated within a region of 2Mpc (the typical size of clusters in the local universe) and are distributed within the filaments traced by the HAEs at z=~2.2. This concentration of massive, dusty starbursts is not centered on the submillimeter-bright radio galaxy which could support the infalling of these sources into the cluster center. Approximately half (6/11) of the SMGs that are covered by the H{alpha} imaging data are associated with HAEs, demonstrating the potential of tracing SMG counterparts with this population. To summarize, our results demonstrate that submillimeter observations may enable us to study (proto)clusters of massive, dusty starbursts.
