- ID:
- ivo://CDS.VizieR/J/MNRAS/396/1075
- Title:
- Globular cluster in nearby dwarf galaxies. II
- Short Name:
- J/MNRAS/396/1075
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare nuclear globular clusters (nGCs) in dwarf galaxies and Galactic GCs with extended (hot) horizontal branches (EHB-GCs) in order to test the suggested external origin of the latter and the conditions at which GC self-enrichment can operate. Using luminosities and structural parameters of nGCs in low-mass (mainly late-type) dwarf galaxies from Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) imaging, we derive the present-day escape velocities (Vesc) of stellar ejecta to reach the cluster tidal radius and compare them with those of EHB-GCs.
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- ID:
- ivo://CDS.VizieR/J/A+A/599/A121
- Title:
- Glycolaldehyde in Perseus young solar analogs
- Short Name:
- J/A+A/599/A121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The earliest evolutionary stages of low-mass protostars are characterised by the so-called hot-corino stage, when the newly born star heats the surrounding material and enrich the gas chemically. Studying this evolutionary phase of solar protostars may help understand the evolution of prebiotic complex molecules in the development of planetary systems. In this paper we focus on the occurrence of glycolaldehyde (HCOCH_2_OH) in young solar analogs by performing the first homogeneous and unbiased study of this molecule in the Class 0 protostars of the nearby Perseus star forming region. We obtained sub-arcsec angular resolution maps at 1.3mm and 1.4mm of glycolaldehyde emission lines using the IRAM Plateau de Bure (PdB) interferometer in the framework of the CALYPSO IRAM large program.
- ID:
- ivo://CDS.VizieR/J/other/Ap/50.194
- Title:
- Groups of stars in NGC 1893
- Short Name:
- J/other/Ap/50.19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The distribution of 255 O-B9-A2, K-G stars and interstellar dust in the direction of the stellar cluster NGC 1893 is studied using V, B-V, and U-B photometric data. Sixteen groups of stars (associations) are discovered at various distances. The first group includes 9 stars of different spectral classes of later types in the Sun's neighborhood lying at a distance of 110pc. The next 3 groups, at distances of 420, 890, and 14300pc, are type B associations and the remaining twelve groups are OB associations. They are designated as Aur 0.11, Aur B 0.43, Aur B 0.89, Aur OB 1.4, Aur OB 2.6, AurOB 3.8, Aur OB 4.6, Aur OB 5.4, Aur OB 6.1, Aur OB 7.4, Aur OB 9.3, Aur OB11.6, Aur OB14.3, Aur OB 17.9, Aur OB 25.9, and Aur OB 31.3. For most of these stars the absorption lies within the range from 0.45m to 5.41m. Such high absorption may be caused by circumstellar absorption as well as by the diffuse nebula IC 410. The dusty matter is distributed non-uniformly in the Aur 0.11, Aur B 0.43, and Aur B 0.89 associations. There is no dust in the space between the associations. There is essentially no dust within the groups (associations) at distances greater than 0.9kpc (see Table 2).
- ID:
- ivo://CDS.VizieR/J/A+A/626/A131
- Title:
- G287.84-0.82 SOFIA and APEX datacubes
- Short Name:
- J/A+A/626/A131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have mapped the G287.84-0.82 cometary globule (with the Treasure Chest cluster embedded in it) in the South Pillars region of Carina (i) in [CII], 63um [OI] , and CO(11-10) using the heterodyne receiver array upGREAT on SOFIA and (ii) in J=2-1 transitions of CO, ^13^CO, C^18^O and J=3-2 transitions of H_2_CO using the APEX telescope in Chile. We use these data to probe the morphology, kinematics, and physical conditions of the molecular gas and the photon dominated regions (PDRs) in G287.84-0.82. The velocity-resolved observations of [CII] and [OI] suggest that the overall structure of the pillar (with red-shifted photo evaporating tails) is consistent with the effect of FUV radiation and winds from eta-Car and O stars in Trumpler 16. The gas in the head of the pillar is strongly influenced by the embedded cluster, whose brightest member is an O9.5 V star, CPD -59 2661. The emission of the [CII] and [OI] lines peak at a position close to the embedded star, while all the other tracers peak at another position lying to the north-east consistent with gas being compressed by the expanding PDR created by the embedded cluster. The molecular gas inside the globule is probed with the J=2-1 transitions of CO and isotopologues as well as H_2_CO, and analyzed using a non-LTE model (escape-probability approach), while we use PDR models to derive the physical conditions of the PDR. We identify at least two PDR gas components; the diffuse part (~10^4cm^-3^) is traced by [CII], while the dense (n~2-8x10^5^cm^-3^) part is traced by [CII], [OI], CO(11-10). Using the the F=2-1 transition of [^13^CII] detected at 50 positions in the region, we derive optical depths (0.9-5), excitation temperatures of [CII] (80-255K), and N(C+) of 0.3-1x10^19^cm^-2^. The total mass of the globule is ~1000M_{sun}_, about half of which is traced by [CII]. The dense PDR gas has a thermal pressure of 10^7-10^8K/cm^3^, which is similar to the values observed in other regions.
- ID:
- ivo://CDS.VizieR/J/AJ/143/3
- Title:
- H{alpha} emission stars in IC 1274
- Short Name:
- J/AJ/143/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- IC 1274 is a faintly luminous nebula lying on the near surface of the Lynds 227 (L227) molecular cloud. Its cavity-like morphology is reminiscent of a blistered star-forming region. Four luminous, early-type (B0-B5) stars are located within a spherical volume ~5' in diameter that appears to be clear of heavy obscuration. Approximately centered in the cleared region is the B0 V star HD 166033, which is thought to be largely responsible for the cavity's excavation. Over 80 H{alpha} emission sources brighter than V~21 have been identified in the region. More than half of these are concentrated in IC 1274 and are presumably members of a faint T Tauri star population. Chandra Advanced CCD Imaging Spectrometer imaging of a nearby suspected pulsar and time-variable {gamma}-ray source (GeV J1809-2327) detected 21 X-ray sources in the cluster vicinity, some of which are coincident with the early-type stars and H{alpha} emitters in IC 1274. Deep (V~22) optical BVRI photometry has been obtained for the cluster region. A distance of 1.82+/-0.3kpc and a mean extinction of AV~1.21+/-0.2mag follow from photometry of the early-type stars. Using pre-main-sequence evolutionary models, we derive a median age for the H{alpha} emitters and X-ray sources of ~1Myr; however, a significant dispersion is present. The displaced material was driven against what remains of the molecular cloud to the east, enabling the formation of the substantial number of T Tauri stars found there. A dispersed population of H{alpha} emitters is also found along the periphery of L227, IC 1275, and IC 4684.
- ID:
- ivo://CDS.VizieR/J/AJ/129/856
- Title:
- Herbig Ae/Be stars in nearby OB associations
- Short Name:
- J/AJ/129/856
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out a study of the early-type stars in nearby OB associations spanning an age range of ~3-16Myr, with the aim of determining the fraction of stars that belong to the Herbig Ae/Be class. We studied the B, A, and F stars in the nearby (<=500pc) OB associations Upper Scorpius, Perseus OB2, Lacerta OB1, and Orion OB1, with membership determined from Hipparcos (Cat. <I/239>) data. We also included in our study the early-type stars in the Trumpler 37 cluster, part of the Cep OB2 association. We obtained spectra for 440 Hipparcos stars in these associations, from which we determined accurate spectral types, visual extinctions, effective temperatures, luminosities and masses, using Hipparcos photometry.
- ID:
- ivo://CDS.VizieR/J/ApJ/753/147
- Title:
- Herschel observations stars in THA
- Short Name:
- J/ApJ/753/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Herschel PACS photometry of 17 B- to M-type stars in the 30Myr old Tucana-Horologium Association. This work is part of the Herschel Open Time Key Programme "Gas in Protoplanetary Systems" (GASPS). 6 of the 17 targets were found to have infrared excesses significantly greater than the expected stellar IR fluxes, including a previously unknown disk around HD30051. These six debris disks were fitted with single-temperature blackbody models to estimate the temperatures and abundances of the dust in the systems. For the five stars that show excess emission in the Herschel PACS photometry and also have Spitzer IRS spectra, we fit the data with models of optically thin debris disks with realistic grain properties in order to better estimate the disk parameters. The model is determined by a set of six parameters: surface density index, grain size distribution index, minimum and maximum grain sizes, and the inner and outer radii of the disk. The best-fitting parameters give us constraints on the geometry of the dust in these systems, as well as lower limits to the total dust masses. The HD105 disk was further constrained by fitting marginally resolved PACS 70{mu}m imaging.
- ID:
- ivo://CDS.VizieR/J/AJ/132/2135
- Title:
- High-resolution spectroscopy in Tr 37
- Short Name:
- J/AJ/132/2135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the Hectochelle multifiber spectrograph, we have obtained high-resolution (R~34000) spectra in the H{alpha} region for a large number of stars in the 4Myr old cluster Tr 37, containing 146 previously known members and 26 newly identified ones. We present the H{alpha} line profiles of all members, compare them to our IR observations of dusty disks (Two Micron All Sky Survey JHK + IRAC + MIPS 24um), use the radial velocities as a membership criterion, and calculate the rotational velocities.
- ID:
- ivo://CDS.VizieR/J/PASP/123/649
- Title:
- HII regions in OB associations
- Short Name:
- J/PASP/123/649
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the data from the NOAO Local Group Survey, we have measured the H{alpha} fluxes of 291 nebulae associated with 21 of the van den Bergh OB associations. We have combined these data together with six-color HST WFPC2 photometry, in order to identify the most UV-bright stars in the region. The simple purpose of this article is to explore the spatial relationships between these components.
- ID:
- ivo://CDS.VizieR/J/MNRAS/387/954
- Title:
- H2 imaging of NGC 1333, L1455, L1448 and B1
- Short Name:
- J/MNRAS/387/954
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss wide-field near-infrared (near-IR) imaging of the NGC 1333, L1448, L1455 and B1 star-forming regions in Perseus. The observations have been extracted from a much larger narrow-band imaging survey of the Taurus-Auriga-Perseus complex. These H_2_ 2.122um observations are complemented by broad-band K imaging, mid-IR imaging and photometry from the Spitzer Space Telescope, and published submillimetre CO J=3-2 maps of high-velocity molecular outflows. We detect and label 85 H_2_ features and associate these with 26 molecular outflows.
