- ID:
- ivo://CDS.VizieR/J/A+A/540/A58
- Title:
- CT1T2 photometry of 26 LMC cluster
- Short Name:
- J/A+A/540/A58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the aim of enlarging the number of studied LMC clusters in the age range 8.0~<log(t)~<9.0, we focus here on a sample of mostly unstudied cluster candidates. We present, for the first time, CCD Washington CT1T2 photometry of stars in the field of 26 LMC clusters. The studied clusters turned out to be small angular size objects with ages within the age range 8.0~<log(t)~< 9.0, which are projected or immersed in dense star fields.
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- ID:
- ivo://CDS.VizieR/J/ApJ/887/19
- Title:
- DECam phot. of Gaia stars in Price-Whelan 1
- Short Name:
- J/ApJ/887/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a young ({tau}~117Myr), low-mass (M~1200M_{sun}_), metal-poor ([Fe/H]~-1.14) stellar association at a heliocentric distance D~28.7kpc, placing it far into the Milky Way (MW) halo. At its present Galactocentric position (R,z)~(23,15)kpc, the association is (on the sky) near the leading arm of the gas stream emanating from the Magellanic Cloud system, but is located ~60{deg} from the Large Magellanic Cloud center on the other side of the MW disk. If the cluster is colocated with HI gas in the stream, we directly measure the distance to the leading arm of the Magellanic stream. The measured distance is inconsistent with Magellanic stream model predictions that do not account for ram pressure and gas interaction with the MW disk. The estimated age of the cluster is consistent with the time of last passage of the leading arm gas through the Galactic midplane; we therefore speculate that this star formation event was triggered by its last disk midplane passage. Most details of this idea remain a puzzle: the Magellanic stream has low column density, the MW disk at large radii has low gas density, and the relative velocity of the leading arm and MW gas is large. However it formed, the discovery of a young stellar cluster in the MW halo presents an interesting opportunity for study. This cluster was discovered with Gaia astrometry and photometry alone, but follow-up DECam photometry was crucial for measuring its properties.
- ID:
- ivo://CDS.VizieR/J/ApJS/213/23
- Title:
- Deep Chandra obs. of the giant HII region N11 in LMC
- Short Name:
- J/ApJS/213/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A very sensitive X-ray investigation of the giant H II region N11 in the Large Megallanic Cloud was performed using the Chandra X-ray Observatory. The 300ks observation reveals X-ray sources with luminosities down to 10^32^erg/s, increasing the number of known point sources in the field by more than a factor of five. Among these detections are 13 massive stars (3 compact groups of massive stars, 9 O stars, and one early B star) with log (L_X_/L_BOL_)~-6.5 to -7, which may suggest that they are highly magnetic or colliding-wind systems. On the other hand, the stacked signal for regions corresponding to undetected O stars yields log (L_X_/L_BOL_)~-7.3, i.e., an emission level comparable to similar Galactic stars despite the lower metallicity. Other point sources coincide with 11 foreground stars, 6 late-B/A stars in N11, and many background objects. This observation also uncovers the extent and detailed spatial properties of the soft, diffuse emission regions, but the presence of some hotter plasma in their spectra suggests contamination by the unresolved stellar population.
- ID:
- ivo://CDS.VizieR/J/ApJ/887/20
- Title:
- Deep Chandra survey of the SMC. III. HMXBs
- Short Name:
- J/ApJ/887/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled the most complete census of high-mass X-ray binaries (HMXBs) in the Small Magellanic Cloud with the aim to investigate the formation efficiency of young accreting binaries in its low-metallicity environment. In total, we use 123 X-ray sources with detections in our Chandra X-ray Visionary Program (XVP), supplemented by 14 additional (likely and confirmed) HMXBs identified by Haberl & Sturm (2016, J/A+A/586/A81) that fall within the XVP area, but are neither detected in our survey (nine sources) nor matched with any of the 127 sources identified in the XVP data (five sources). Specifically, we examine the number ratio of the HMXBs [N(HMXBs)] to (a) the number of OB stars, (b) the local star formation rate (SFR), and (c) the stellar mass produced during the specific star formation burst, all as a function of the age of their parent stellar populations. Each of these indicators serves a different role, but in all cases we find that the HMXB formation efficiency increases as a function of time (following a burst of star formation) up to ~40-60Myr, and then gradually decreases. The formation efficiency peaks at ~30-40Myr with average rates of N(HMXB)/SFR=339_-83_^+78^(M_{sun}_/yr)^-1^, and N(HMXB)/M*=(8.74_-0.92_^+1.0^)x10^-6^M_{sun}_^-1^, in good agreement with previous estimates of the average formation efficiency in the broad ~20-60Myr age range.
- ID:
- ivo://CDS.VizieR/III/113A
- Title:
- Deep Objective-Prism Survey for LMC Members
- Short Name:
- III/113A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog contains 1273 proven or probable Large Magellanic Cloud (LMC) members, identified on plates taken with the Curtis-Schmidt telescope at Cerro Tololo Inter-American Observatory in Chile. The stars are generally brighter than photographic magnitude 14 and are identified on charts published by Hodge and Wright (1967) and reproduced in the source publication (1970CoTol..89....1S). Approximate spectral types were determined by examination of the 580 Angstroms/mm (at H{gamma}) objective-prism spectra; approximate 1975 positions were obtained by measuring relative to the 1975 coordinate grids on the Uppsala-Mount Stromlo Atlas of the LMC (Gascoigne and Westerlund 1961), and approximate photographic magnitudes were determined by averaging image density measures from the plates and image-diameter measures on the "B" charts of Hodge and Wright (1967SAOP.4699....1H). The catalog includes an identification number (Sk), HD(E) number, Cape Photographic Durchmusterung number, right ascension and declination (equinox B1975), spectral type, photographic magnitude, and alternate identifications. The machine version, updated in September 1986, includes corrections supplied by the author in 1985; thus, it differs somewhat from the published version. Accurate positions, and cross-identifications with the modern surveys, were determined by Brian Skiff in 2008, and make up the "sk_pos.dat" file. This work is based on a file prepared through great effort by Mati Morel in 1999. Brian Skiff examined every object on DSS cut-outs to make sure the star chosen matched the Sanduleak charts. The Goddard SkyView utility was used, looking at an 0.07{deg} (4'x4') field from the DSS1 (short-V plate), DSS2 far-red, and 2MASS J-band images. These three have the shallowest effective exposure (these are bright stars!), and usually the best image quality to check for companions etc as well as star colors. Precise coordinates were then obtained via VizieR mainly from UCAC2, but occasionally elsewhere as indicated in the column 's' for each star. The list was also matched against Tycho-2 and the GSC, and the Massey et al. photometric survey from 2002ApJS..141...81M (Cat. II/236). The file "sk_pos.dat" includes also Sanduleak's original approximate spectral types, and approximative V magnitudes that Mati Morel adopted from the work of the Marseille group; some missing HD(E) and CPD names were also added. It should be noticed also that the file has 1275 entries, 3 stars being resolved into resolved pairs. The notes includes Sanduleak's original notes, as well as remarks added by Brian Skiff in the course of his verifications.
- ID:
- ivo://CDS.VizieR/II/228A
- Title:
- DENIS Catalogue toward Magellanic Clouds (DCMC)
- Short Name:
- II/228A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the first version of a complete near-IR point source catalogue towards the Magellanic Clouds extracted from the data obtained with the DEep Near Infraread Survey of the Southern Sky (DENIS). The catalogue covers an area of 19.87x16 square degrees centered on (05:27:20-69:00:00) for the Large Magellanic Cloud (LMC), and 14.7x10 square degrees centered on (01:02:40-73:00:00) for the Small Magellanic Cloud (SMC). It contains the sources detected in at least 2 of the 3 photometric bands I (Gunn-i centered at 0.8{mu}m), J (centered at 1.25{mu}m), and K_s_ (centered at 2.15{mu}m). The spatial resolution is 1" in I and 3" in the J and K bands, and the limiting magnitudes are I=18, J=16 and K_s_=14. 70% of the detected sources are real members of the Magellanic Clouds, and consist mainly of red giants, asymptotic giant branch stars and supergiants.
- ID:
- ivo://CDS.VizieR/J/ApJ/792/43
- Title:
- Detected sources in the region of Magellanic Stream
- Short Name:
- J/ApJ/792/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the discrete clouds and filaments in the Magellanic Stream using a new high-resolution survey of neutral hydrogen (H I) conducted with the H75 array of the Australia Telescope Compact Array, complemented by single-dish data from the Parkes Galactic All-Sky Survey. From the individual and combined data sets, we have compiled a catalog of 251 clouds and listed their basic parameters, including a morphological description useful for identifying cloud interactions. We find an unexpectedly large number of head-tail clouds in the region. The implication for the formation mechanism and evolution is discussed. The filaments appear to originate entirely from the Small Magellanic Cloud and extend into the northern end of the Magellanic Bridge.
- ID:
- ivo://CDS.VizieR/J/MNRAS/353/601
- Title:
- 2dF survey of the Small Magellanic Cloud
- Short Name:
- J/MNRAS/353/601
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of new spectral types for hot, luminous stars in the Small Magellanic Cloud. The catalogue contains 4161 objects, giving an order of magnitude increase in the number of SMC stars with published spectroscopic classifications. The targets are primarily B- and A-type stars (2862 and 853 objects respectively), with 1 Wolf-Rayet, 139 O-type, and 306 FG stars, sampling the main sequence to ~mid-B. The selection and classification criteria are described, and objects of particular interest are discussed, including UV-selected targets from the Ultraviolet Imaging Telescope (UIT) experiment, Be and B[e] stars, `anomalous A supergiants', and composite-spectrum systems. We examine the incidence of Balmer-line emission, and the relationship between H-gamma equivalent width and absolute magnitude for BA stars.
- ID:
- ivo://CDS.VizieR/J/A+A/550/A108
- Title:
- DIB in VLT-FLAMES Tarantula Survey
- Short Name:
- J/A+A/550/A108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Tarantula Nebula (a.k.a. 30 Dor) is a spectacular star-forming region in the Large Magellanic Cloud (LMC), seen through gas in the Galactic disc and halo. Diffuse interstellar bands (DIBs) offer a unique probe of the diffuse, cool-warm gas in these regions. The aim is to use DIBs as diagnostics of the local interstellar conditions, whilst at the same time deriving properties of the yet-unknown carriers of these enigmatic spectral features. Spectra of over 800 early-type stars from the Very Large Telescope Flames Tarantula Survey (VFTS) were analysed. Maps were created, separately, for the Galactic and LMC absorption in the DIBs at 4428 and 6614{AA} and - in a smaller region near the central cluster R 136 - neutral sodium (the NaI D doublet); we also measured the DIBs at 5780 and 5797{AA}.
- ID:
- ivo://CDS.VizieR/J/MNRAS/454/4013
- Title:
- DIBs in Magellanic Clouds and Milky Way
- Short Name:
- J/MNRAS/454/4013
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Diffuse interstellar bands (DIBs) trace warm neutral and weakly ionized diffuse interstellar medium (ISM). Here we present a dedicated, high signal-to-noise spectroscopic survey of two of the strongest DIBs, at 5780 and 5797{AA}, in optical spectra of 666 early-type stars in the Small and Large Magellanic Clouds, along with measurements of the atomic NaI D and CaII K lines. The resulting maps show for the first time the distribution of DIB carriers across large swathes of galaxies, as well as the foreground Milky Way ISM. We confirm the association of the 5797{AA} DIB with neutral gas, and the 5780{AA} DIB with more translucent gas, generally tracing the star-forming regions within the Magellanic Clouds. Likewise, the NaI D line traces the denser ISM whereas the CaII K line traces the more diffuse, warmer gas. The CaII K line has an additional component at ~200-220km/s seen towards both Magellanic Clouds; this may be associated with a pan-Magellanic halo. Both the atomic lines and DIBs show sub-pc-scale structure in the Galactic foreground absorption; the 5780 and 5797{AA} DIBs show very little correlation on these small scales, as do the CaII K and NaI D lines. This suggests that good correlations between the 5780 and 5797{AA} DIBs, or between CaII K and NaI D, arise from the superposition of multiple interstellar structures. Similarity in behaviour between DIBs and NaI in the Small Magellanic Cloud (SMC), Large Magellanic Cloud (LMC) and Milky Way suggests the abundance of DIB carriers scales in proportion to metallicity.
