- ID:
- ivo://CDS.VizieR/J/ApJ/783/122
- Title:
- AllWISE motion survey
- Short Name:
- J/ApJ/783/122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The AllWISE processing pipeline has measured motions for all objects detected on Wide-field Infrared Survey Explorer (WISE) images taken between 2010 January and 2011 February. In this paper, we discuss new capabilities made to the software pipeline in order to make motion measurements possible, and we characterize the resulting data products for use by future researchers. Using a stringent set of selection criteria, we find 22445 objects that have significant AllWISE motions, of which 3525 have motions that can be independently confirmed from earlier Two Micron All Sky Survey (2MASS) images, yet lack any published motions in SIMBAD. Another 58 sources lack 2MASS counterparts and are presented as motion candidates only. Limited spectroscopic follow-up of this list has already revealed eight new L subdwarfs. These may provide the first hints of a "subdwarf gap" at mid-L types that would indicate the break between the stellar and substellar populations at low metallicities (i.e., old ages). Another object in the motion list --WISEA J154045.67-510139.3-- is a bright (J~9mag) object of type M6; both the spectrophotometric distance and a crude preliminary parallax place it ~6pc from the Sun. We also compare our list of motion objects to the recently published list of 762 WISE motion objects from Luhman (2014, J/ApJ/781/4). While these first large motion studies with WISE data have been very successful in revealing previously overlooked nearby dwarfs, both studies missed objects that the other found, demonstrating that many other nearby objects likely await discovery in the AllWISE data products.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/883/6
- Title:
- AllWISE & NEOWISE LCs of Red MSX massive YSOs
- Short Name:
- J/ApJ/883/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We systematically investigate the mid-infrared (MIR; {lambda}>3{mu}m) time variability of uniformly selected ~800 massive young stellar objects (MYSOs) from the Red Midcourse Space Experiment Source survey. Out of the 806 sources, we obtain reliable 9yr long MIR magnitude variability data of 331 sources at the 3.4{mu}m (W1) and 4.6{mu}m (W2) bands by cross-matching the MYSO positions with ALLWISE and NEOWISE catalogs. After applying the variability selections using ALLWISE data, we identify five MIR-variable candidates. The light curves show various classes, with the periodic, plateau-like, and dipper features. Out of the obtained two color-magnitude diagram of W1 and W1-W2, one shows "bluer when brighter and redder when fainter" trends in variability, suggesting change in extinction or accretion rate. Finally, our results show that G335.9960-00.8532 has a periodic light curve, with an ~690d cycle. Spectral energy density model fitting results indicate that G335.9960-00.8532 is a relatively evolved MYSO; thus, we may be witnessing the very early stages of a hyper- or ultra-compact HII region, a key source for understanding MYSO evolution.
- ID:
- ivo://CDS.VizieR/J/ApJ/826/16
- Title:
- ALMA and GeMS observations of the OMC1 region
- Short Name:
- J/ApJ/826/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present ALMA observations of the Orion Nebula that cover the OMC1 outflow region. Our focus in this paper is on compact emission from protoplanetary disks. We mosaicked a field containing ~600 near-IR-identified young stars, around which we can search for sub-millimeter emission tracing dusty disks. Approximately 100 sources are known proplyds identified with the Hubble Space Telescope. We detect continuum emission at 1mm wavelengths toward ~20% of the proplyd sample, and ~8% of the larger sample of near-IR objects. The noise in our maps allows 4{sigma} detection of objects brighter than ~1.5mJy, corresponding to protoplanetary disk masses larger than 1.5M_J_ (using standard assumptions about dust opacities and gas-to-dust ratios). None of these disks are detected in contemporaneous CO(2-1) or C^18^O(2-1) observations, suggesting that the gas-to-dust ratios may be substantially smaller than the canonical value of 100. Furthermore, since dust grains may already be sequestered in large bodies in Orion Nebula cluster (ONC) disks, the inferred masses of disk solids may be underestimated. Our results suggest that the distribution of disk masses in this region is compatible with the detection rate of massive planets around M dwarfs, which are the dominant stellar constituent in the ONC.
- ID:
- ivo://CDS.VizieR/J/A+A/633/A115
- Title:
- ALMA and NACO observations towards V1400 Cen
- Short Name:
- J/A+A/633/A115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our aim was to directly detect the thermal emission of the putative exoring system responsible for the complex deep transits observed in the light curve for the young Sco-Cen star 1SWASP J140747.93-394542.6 (V1400 Cen, hereafter J1407), confirming it as the occulter seen in May 2007, and to determine its orbital parameters with respect to the star. We used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the field centred on J1407 in the 340GHz (Band 7) continuum in order to determine the flux and astrometric location of the ring system relative to the star. We used the VLT/NACO camera to observe the J1407 system in March 2019 and to search for the central planetary mass object at thermal infrared wavelengths. We detect no point source at the expected location of J1407, and derive an upper limit 3{sigma} level of 57.6uJy. There is a point source detected at an angular separation consistent with the expected location for a free-floating ring system that occulted J1407 in May 2007, with a flux of 89uJy consistent with optically thin dust surrounding a massive substellar companion. At 3.8 microns with the NACO camera, we detect the star J1407 but no other additional point sources within 1.3 arcseconds of the star, with a lower bound on the sensitivity of 6MJup at the location of the ALMA source, and down to 4MJup in the sky background limit. The ALMA upper limit at the location of J1407 implies that a hypothesised bound ring system is composed of dust smaller than 1 mm in size, implying a young ring structure. The detected ALMA source has multiple interpretations, including: (i) it is an unbound substellar object surrounded by warm dust in Sco-Cen with an upper mass limit of 6M_Jup_, or (ii) it is a background galaxy.
- ID:
- ivo://CDS.VizieR/J/ApJ/832/187
- Title:
- ALMA and VLA radio continuum obs. of NGC 6334I
- Short Name:
- J/ApJ/832/187
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Very Large Array and Atacama Large Millimeter/submillimeter Array imaging of the deeply embedded protostellar cluster NGC 6334I from 5cm to 1.3mm at angular resolutions as fine as 0.17" (220au). The dominant hot core MM1 is resolved into seven components at 1.3mm, clustered within a radius of 1000au. Four of the components have brightness temperatures >200K, radii ~300au, minimum luminosities ~10^4^L_{sun}_, and must be centrally heated. We term this new phenomenon a "hot multi-core." Two of these objects also exhibit compact free-free emission at longer wavelengths, consistent with a hypercompact HII region (MM1B) and a jet (MM1D). The spatial kinematics of the water maser emission centered on MM1D are consistent with it being the origin of the high-velocity bipolar molecular outflow seen in CO. The close proximity of MM1B and MM1D (440au) suggests a proto-binary or a transient bound system. Several components of MM1 exhibit steep millimeter spectral energy distributions indicative of either unusual dust spectral properties or time variability. In addition to resolving MM1 and the other hot core (MM2) into multiple components, we detect five new millimeter and two new centimeter sources. Water masers are detected for the first time toward MM4A, confirming its membership in the protocluster. With a 1.3mm brightness temperature of 97K coupled with a lack of thermal molecular line emission, MM4A appears to be a highly optically thick 240L_{sun}_ dust core, possibly tracing a transient stage of massive protostellar evolution. The nature of the strongest water maser source CM2 remains unclear due to its combination of non-thermal radio continuum and lack of dust emission.
- ID:
- ivo://CDS.VizieR/J/ApJ/855/49
- Title:
- ALMA astrochemical obs. of the merger NGC 3256
- Short Name:
- J/ApJ/855/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In external galaxies, molecular composition may be influenced by extreme environments such as starbursts and galaxy mergers. To study such molecular chemistry, we observed the luminous infrared galaxy and merger NGC 3256 using the Atacama Large Millimeter/submillimeter Array. We covered most of the 3 and 1.3mm bands for a multispecies, multitransition analysis. We first analyzed intensity ratio maps of selected lines such as HCN/HCO^+^, which shows no enhancement at an active galactic nucleus. We then compared the chemical compositions within NGC 3256 at the two nuclei, tidal arms, and positions with influence from galactic outflows. We found the largest variation in SiO and CH_3_OH, species that are likely to be enhanced by shocks. Next, we compared the chemical compositions in the nuclei of NGC 3256, NGC 253, and Arp 220; these galactic nuclei have varying star formation efficiencies. Arp 220 shows higher abundances of SiO and HC_3_N than NGC 3256 and NGC 253. Abundances of most species do not show a strong correlation with star formation efficiencies, although the CH_3_CCH abundance seems to have a weak positive correlation with the star formation efficiency. Lastly, the chemistry of spiral arm positions in NGC 3256 is compared with that of W51, a Galactic molecular cloud complex in a spiral arm. We found higher fractional abundances of shock tracers, and possibly also a higher dense gas fraction in NGC 3256 compared with W51.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/1512
- Title:
- ALMA calibrator continuum observations catalog
- Short Name:
- J/MNRAS/478/1512
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of ALMA flux density measurements of 754 calibrators, obtained during the majority of the ALMA science observations between 2012 August and 2017 September, for a total of 16263 observations in different bands and epochs. The flux densities were measured by reprocessing the ALMA images generated in the framework of the ALMACAL project, with a new code developed by the Italian node of the European ALMA Regional Centre. A search in the online data bases yielded redshift measurements for 589 sources (about 78 per cent of the total). Almost all sources are flat spectrum, based on their low-frequency spectral index, and have properties consistent with being blazars of different types.
- ID:
- ivo://CDS.VizieR/J/ApJ/860/124
- Title:
- ALMA continuum emission obs. of MWC 758 disk
- Short Name:
- J/ApJ/860/124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spatially resolved structures in protoplanetary disks hint at unseen planets. Previous imaging observations of the transitional disk around MWC 758 revealed an inner cavity, a ring-like outer disk, emission clumps, and spiral arms, all possibly generated by companions. We present ALMA dust continuum observations of MWC 758 at 0.87mm wavelength with 43x39mas angular resolution (6.9x6.2au) and 20{mu}Jy/beam rms. The central submillimeter emission cavity is revealed to be eccentric; once deprojected, its outer edge can be well fitted by an ellipse with an eccentricity of 0.1 and one focus on the star. The broad ring-like outer disk is resolved into three narrow rings with two gaps in between. The outer two rings tentatively show the same eccentricity and orientation as the innermost ring bounding the inner cavity. The two previously known dust emission clumps are resolved in both the radial and azimuthal directions, with radial widths equal to ~4x the local scale height. Only one of the two spiral arms previously imaged in near-infrared (NIR) scattered light is revealed in ALMA dust emission, at a slightly larger stellocentric distance owing to projection effects. We also submit evidence of disk truncation at ~100au based on comparing NIR imaging observations with models. The spirals, the north clump, and the truncated disk edge are all broadly consistent with the presence of one companion exterior to the spirals at roughly 100au.
- ID:
- ivo://CDS.VizieR/J/A+A/626/A36
- Title:
- ALMA continuum fits files of G9.62+0.19
- Short Name:
- J/A+A/626/A36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used Band 7 ALMA observations in full polarisation mode to analyse the polarised dust emission of the massive star forming region G9.62+0.19. We estimated the magnetic field strength via the Davis-Chandrasekhar-Fermi and structure function methods. We resolve several protostellar cores embedded in a bright and dusty filamentary structure. The magnetic field is orientated along the filament and appears perpendicular to the direction of the outflows. The polarisation vectors present ordered patterns and the cores showing polarised emission are less fragmented. We suggest an evolutionary sequence of the magnetic field, and the less evolved hot core exhibits a stronger magnetic field than the more evolved hot core. An average magnetic field strength of the order of 11mG was derived, from which we obtain a low turbulent-to-magnetic energy ratio, indicating that turbulence does not significantly contribute to the stability of the clump. We report a detection of linear polarisation from thermal line emission, probably from methanol or carbon dioxide, and we tentatively compared linear polarisation vectors from our observations with previous linearly polarised OH masers observations.
- ID:
- ivo://CDS.VizieR/J/A+A/648/A33
- Title:
- ALMA continuum images of TW Hya
- Short Name:
- J/A+A/648/A33
- Date:
- 08 Feb 2022 14:06:34
- Publisher:
- CDS
- Description:
- A key piece of information to understand the origin and role of protoplanetary disk substructures is their dust content. In particular, disk substructures associated with gas pressure bumps can work as dust traps, accumulating grains and reaching the necessary conditions to trigger the streaming instability. In order to shed some light on the origin and role that disk substructures play in planet formation, we aim to characterize the dust content of substructures in the disk of TW Hya. We present Atacama Large Millimeter Array (ALMA) observations of TW Hya at 3.1mm with ~50 milliarcsecond resolution. These new data were combined with archival high angular resolution ALMA observations at 0.87mm, 1.3mm, and 2.1mm. We analyze these multiwavelength data to infer a disk radial profile of the dust surface density, maximum particle size, and slope of the particle size distribution. Most previously known annular substructures in the disk of TW Hya are resolved at the four wavelengths. Inside the inner 3au cavity, the 2.1mm and 3.1mm images show a compact source of free-free emission, likely associated with an ionized jet. Our multiwavelength analysis of the dust emission shows that the maximum particle size in the disk of TW Hya is >1mm. The inner 20au are completely optically thick at all four bands, which results in the data tracing different disk heights at different wavelengths. Coupled with the effects of dust settling, this prevents the derivation of accurate density and grain size estimates in these regions. At r>20au, we find evidence of the accumulation of large dust particles at the position of the bright rings, indicating that these are working as dust traps. The total dust mass in the disk is between 250 and 330M_{sun}_, which represents a gas-to-dust mass ratio between 50 and 70. Our mass measurement is a factor of 4.5-5.9 higher than the mass that one would estimate using the typical assumptions of large demographic surveys. Our results indicate that the ring substructures in TW Hya are ideal locations to trigger the streaming instability and form new generations of planetesimals.
