- ID:
- ivo://CDS.VizieR/J/ApJ/751/115
- Title:
- Millimeter emission from Taurus binary systems
- Short Name:
- J/ApJ/751/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a high angular resolution millimeter-wave dust continuum imaging survey of circumstellar material associated with the individual components of 23 multiple star systems in the Taurus-Auriga young cluster. Combined with previous measurements in the literature, these new data permit a comprehensive look at how the millimeter luminosity (a rough tracer of disk mass) relates to the separation and mass of a stellar companion. Approximately one-third (28%-37%) of the individual stars in multiple systems have detectable millimeter emission, an incidence rate half that for single stars (~62%) which does not depend on the number of companions. There is a strong, positive correlation between the luminosity and projected separation (a_p_) of a stellar pair. Wide pairs (a_p_>300AU) have a similar luminosity distribution as single stars, medium pairs (a_p_{approx}30-300AU) are a factor of five fainter, and close pairs (a_p_<30AU) are ~5x fainter yet (aside from a small, but notable population of bright circumbinary disks). In most cases, the emission is dominated by a disk around the primary (or a wide tertiary in hierarchical triples), but there is no clear relationship between luminosity and stellar mass ratio.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/602/A37
- Title:
- Millimeter RRL in ATLASGAL-selected massive clumps
- Short Name:
- J/A+A/602/A37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of millimeter wavelength radio recombination lines (mm-RRLs) are used to search for HII regions in an unbiased way that is complementary to many of the more traditional methods previously used (e.g., radio continuum, far-infrared colors, maser emission). The mm-RRLs can be used to derive physical properties of HII regions and to provide velocity information of ionized gas. We carried out targeted mm-RRL observations (39<= principal quantum number (n) <=65 and {Delta}n = 1, 2, 3, and 4, named Hn{alpha}, Hn{beta}, Hn{gamma}, and Hn{delta}) using the IRAM 30m and Mopra 22m telescopes. In total, we observed 976 compact dust clumps selected from a catalog of ~10000 sources identified by the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL). The sample was selected to ensure a representative mix of star-forming and quiescent clumps such that a variety of different evolutionary stages is represented. Approximately half of the clumps are mid-infrared quiet while the other half are mid-infrared bright. We detected Hn{alpha} mm-RRL emission toward 178 clumps; Hn{beta}, Hn{gamma}, and Hn{delta} were also detected toward 65, 23, and 22 clumps, respectively. This is the largest sample of mm-RRLs detections published to date. Comparing the positions of these clumps with radio continuum surveys we identified compact radio counterparts for 134 clumps, confirming their association with known HII regions. The nature of the other 44 detections is unclear, but 8 detections are thought to be potentially new HII regions while the mm-RRL emission from the others may be due to contamination from nearby evolved HII regions. Broad linewidths are seen toward nine clumps (linewidth>40km/s) revealing significant turbulent motions within the ionized gas; in the past, such wide linewidths were found toward very compact and dense HII regions. We find that the systemic velocity of the associated dense molecular gas, traced by H^13^CO^+^(1-0), is consistent with the mm-RRL velocities and confirms them as embedded HII regions. We also find that the linewidth of the H^13^CO^+^(1-0) emission is significantly wider than those without mm-RRL detection, indicating a physical connection between the embedded H II region and their natal environments. We also find a correlation between the integrated fluxes of the mm-RRLs and the 6cm continuum flux densities of their radio counterparts (the correlation coefficient, {rho}, is 0.70). By calculating the electron densities we find that the mm-RRL emission is associated with HII regions with n_e_<10^5^cm^3^ and HII region diameter >0.03pc. We detected mm-RRLs toward 178 clumps and identified eight new HII region candidates. The broad mm-RRL from nine clumps may indicate that they arise in very young hyper-compact HII regions. The mm-RRLs trace the radio continuum sources detected by high-resolution observations and their line parameters show associations with the embedded radio sources and their parental molecular clumps.
- ID:
- ivo://CDS.VizieR/J/ApJ/719/763
- Title:
- Millimeter-wave sources in the SPT survey
- Short Name:
- J/ApJ/719/763
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of an 87deg^2^ point-source survey centered at R.A. 5h30m, decl. -55{deg} taken with the South Pole Telescope at 1.4 and 2.0mm wavelengths with arcminute resolution and milli-Jansky depth. Based on the ratio of flux in the two bands, we separate the detected sources into two populations, one consistent with synchrotron emission from active galactic nuclei and the other consistent with thermal emission from dust. We present source counts for each population from 11 to 640mJy at 1.4mm and from 4.4 to 800mJy at 2.0mm. The 2.0mm counts are dominated by synchrotron-dominated sources across our reported flux range; the 1.4mm counts are dominated by synchrotron-dominated sources above ~15mJy and by dust-dominated sources below that flux level. We detect 141 synchrotron-dominated sources and 47 dust-dominated sources at signal-to-noise ratio S/N>4.5 in at least one band. All of the most significantly detected members of the synchrotron-dominated population are associated with sources in previously published radio catalogs. Some of the dust-dominated sources are associated with nearby (z<<1) galaxies whose dust emission is also detected by the Infrared Astronomy Satellite. However, most of the bright, dust-dominated sources have no counterparts in any existing catalogs. We argue that these sources represent the rarest and brightest members of the population commonly referred to as submillimeter galaxies (SMGs).
- ID:
- ivo://CDS.VizieR/J/AJ/129/1049
- Title:
- Millimetric and sub-mm obs. of solar-type stars
- Short Name:
- J/AJ/129/1049
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present submillimeter (Caltech Submillimeter Observatory 350{mu}m) and millimeter (Swedish-ESO Submillimetre Telescope [SEST] 1.2mm, Owens Valley Radio Observatory [OVRO] 3mm) photometry for 127 solar-type stars from the Formation and Evolution of Planetary Systems Spitzer Legacy program (FEPS, Meyer et al. 2004ApJS..154..422M) that have masses between ~0.5 and 2.0M_Sun_ and ages from ~3Myr to 3Gyr.
- ID:
- ivo://CDS.VizieR/J/ApJ/641/389
- Title:
- Millimetric observations of IRDC cores
- Short Name:
- J/ApJ/641/389
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Infrared dark clouds (IRDCs) are dense molecular clouds seen as extinction features against the bright mid-infrared Galactic background. Millimeter continuum maps toward 38 IRDCs reveal extended cold dust emission to be associated with each of the IRDCs. IRDCs range in morphology from filamentary to compact and have masses of 120 to 16000M_{sun}_, with a median mass of 940M_{sun}_. Each IRDC contains at least one compact (0.5pc) dust core and most show multiple cores. We find 140 cold millimeter cores unassociated with MSX 8{mu}m emission.
- ID:
- ivo://CDS.VizieR/J/ApJ/672/558
- Title:
- MIPS observations of h and {chi} Persei
- Short Name:
- J/ApJ/672/558
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe Spitzer MIPS observations of the double cluster, h and {chi} Persei, covering a ~0.6deg^2^ area surrounding the cores of both clusters. The data are combined with IRAC and 2MASS data to investigate ~616 sources from 1.25-24um. We use the long-baseline Ks-[24] color to identify two populations with IR excess indicative of circumstellar material: Be stars with 24um excess from optically thin free-free emission, and 17 fainter sources (J~14-15) with [24] excess consistent with a circumstellar disk. The frequency of IR excess for the fainter sources increases from 4.5 to 24um. The IR excess is likely due to debris from the planet formation process. The wavelength-dependent behavior is consistent with an inside-out clearing of circumstellar disks. A comparison of the 24um excess population in h and {chi} Per sources with results for other clusters shows that 24um emission from debris disks "rises" from 5 to 10Myr, peaks at ~10-15Myr, and then "falls" from ~15-20Myr to 1Gyr.
267. MIPS 24um nebulae
- ID:
- ivo://CDS.VizieR/J/MNRAS/405/1047
- Title:
- MIPS 24um nebulae
- Short Name:
- J/MNRAS/405/1047
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Massive evolved stars lose a large fraction of their mass via copious stellar wind or instant outbursts. During certain evolutionary phases, they can be identified by the presence of their circumstellar nebulae. In this paper, we present the results of a search for compact nebulae (reminiscent of circumstellar nebulae around evolved massive stars) using archival 24um data obtained with the Multiband Imaging Photometer for Spitzer. We have discovered 115 nebulae, most of which bear a striking resemblance to the circumstellar nebulae associated with luminous blue variables (LBVs) and late WN-type (WNL) Wolf-Rayet (WR) stars in the Milky Way and the Large Magellanic Cloud (LMC).
- ID:
- ivo://CDS.VizieR/J/MNRAS/459/1403
- Title:
- M31 IRAC 3.6/4.5um extended survey
- Short Name:
- J/MNRAS/459/1403
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results from an extended survey of the Andromeda galaxy (M31) using 41.1h of observations by Spitzer-IRAC at 3.6 and 4.5{mu}m. This survey extends previous observations to the outer disc and halo, covering total lengths of 44 and 66 along the minor and major axes, respectively. We have produced surface brightness profiles by combining the integrated light from background-corrected maps with stellar counts from a new catalogue of point sources. Using auxiliary catalogues, we have carried out a statistical analysis in colour-magnitude space to discriminate M31 objects from foreground Milky Way stars and background galaxies. The catalogue includes 426 529 sources, of which 66 per cent have been assigned probability values to identify M31 objects with magnitude depths of [3.6]=19.0+/-0.2, [4.5]=18.7+/-0.2. We discuss applications of our data for constraining the stellar mass and characterizing point sources in the outer radii.
- ID:
- ivo://CDS.VizieR/J/ApJ/806/231
- Title:
- MISFITS survey: HCO+ obs. of Spitzer YSOs
- Short Name:
- J/ApJ/806/231
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an HCO^+^ J=3->2 survey of Class 0+I and Flat SED young stellar objects (YSOs) found in the Gould Belt clouds by surveys with Spitzer. Our goal is to provide a uniform Stage 0+I source indicator for these embedded protostar candidates. We made single point HCO^+^ J=3->2 measurements toward the source positions at the CSO and APEX of 546 YSOs (89% of the Class 0+I + Flat SED sample). Using the criteria from van Kempen et al. (2009, J/A+A/498/167), we classify sources as Stage 0+I or bona fide protostars and find that 84% of detected sources meet the criteria. We recommend a timescale for the evolution of Stage 0+I (embedded protostars) of 0.54Myr. We find significant correlations of HCO^+^ integrated intensity with {alpha} and T_bol_ but not with L_bol_. The detection fraction increases smoothly as a function of {alpha} and L_bol_, while decreasing smoothly with T_bol_. Using the Stage 0+I sources tightens the relation between protostars and high extinction regions of the cloud; 89% of Stage I sources lie in regions with A_V_>8mag. Class 0+I and Flat SED YSOs that are not detected in HCO^+^ have, on average, a factor of ~2 higher T_bol_ and a factor of ~5 lower L_bol_than YSOs with HCO^+^ detections. We find less YSO contamination, defined as the number of undetected YSOs divided by the total number surveyed, for sources with T_bol_<~600K and L_bol_>~1L_{sun}_. The contamination percentage is >90% at A_V_<4mag and decreases as A_V_ increases.
- ID:
- ivo://CDS.VizieR/J/A+A/531/A50
- Title:
- 1.3mm and 3mm emission maps or 4 Ae/Be stars
- Short Name:
- J/A+A/531/A50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Herbig Ae stars (HAe) are the precursors of Vega-type systems and, therefore, crucial objects in planet formation studies. Thus far, only a few disks associated with HAe stars have been studied using millimetre interferometers. Our aim is to determine the dust evolution and the lifetime of the disks associated with Herbig Ae stars. We imaged the continuum emission at ~3mm and ~1.3mm of the Herbig Ae/Be stars BD+61154, RR Tau, VY Mon and LkH{alpha} 198 using the Plateau de Bure Interferometer (PdBI). These stars are in the upper end of the stellar mass range of the Herbig Ae stars (M_*_>3M_{sun}_). Our measurements were used to complete the Spectral Energy Distribution (SED). The modelling of the SED, in particular the FIR-mm part, allow us to determine the masses and dust properties of these disks. We detected the disks associated with BD+61154, RR Tau and VY Mon with disk masses of 0.35M_{sun}_, 0.05M_{sun}_ and 0.40M_{sun}_ respectively. The disk around LkH{alpha} 198 was not detected with an upper limit to the disk mass of 0.004M_{sun}_. We detected, however, the disks associated with the younger stellar objects LkH{alpha} 198--IR and LkH{alpha} 198--mm that are located in the vicinity of LkH{alpha} 198. The fitting of the mm part of the SED reveal that the grains in the mid-plane of the disks around BD+61154, RR Tau and VY Mon have sizes of ~1-1000um. Therefore, grains have not grown to centimetre sizes in these disks yet. These massive (M_*_>3M_{sun}_) and young (~1Myr) HAe stars are surrounded by massive (>~0.04M_{sun}_) disks with grains of micron-millimetre sizes. Although grain growth is proceeding in these disks, their evolutionary stage is prior to the formation of planetesimals. These disks are less evolved than those detected around T Tauri and Herbig Be stars.
