- ID:
- ivo://CDS.VizieR/J/A+A/357/1020
- Title:
- JHK photometry in NGC 6334 IV
- Short Name:
- J/A+A/357/1020
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Sub-arcsecond JHK images of the star formation region NGC 6334 IV covering 14.7arcmin^2^ have been obtained. These were supplemented by H_2_ and Br{gamma} images of the central 2arcmin^2^. A total of 1238sources brighter than K=~17 were detected. Due to the very high extinction in this region, only 685 of these are brighter at 1.2{mu}m than our limit, J=~20. Only less than 5% of the sources exhibit excess emission at {lambda}>2.0{mu}m and they are scattered over the whole area covered. No evidence of a developed stellar cluster was found, but a small number of luminous (O-B2) young stellar objects were detected. These are embedded in the densest part of the molecular cloud that is at the centre of a giant bipolar structure seen in the radio and the infrared. This morphology is the result of the effect of massive stellar winds originating from the centre of a dense molecular toroid which collimates the outflow material giving rise to two lobes of thermal gas and dust emission. We confirm that the extinction is higher toward the southern lobe than toward the northern one but both are less reddened than their immediate surroundings. A new centre of active massive star formation is reported to the east of the central region. Close to a (sub)millimeter emission peak, a large infrared nebula with several point-like sources was found at 2.2{mu}m. The discovery of a small embedded low-luminosity bipolar object in the vicinity of one of the giant lobes is also reported. For a description of the JHK photometric system, see e.g. <GCPD/09>
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/360/1107
- Title:
- JHK photometry in Sh2-88B HII region
- Short Name:
- J/A+A/360/1107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric study of the compact HII region Sh2-88B and its associated stellar cluster. The positions and JHKmagnitudes are obtained for 125 stars over an 80"x80" field centered on the region. The region has two components , called Sh2-88B1 and Sh2-88B2. B1 is a compact cometary HII region associated with a cluster containing several massive stars. The dominant exciting star, at t he center of the cometary structure, has an ionizing radiation flux corresponding to a spectral type in the range O8.5V-O9.5V. It is highly reddened, with a visual extinction in the 30-42mag range, and exhibits a near-IR excess. B1 has a simple morphology, with the ionized and neutral gas clearly separated. Its unidentified infrared band (UIB) emission, observed by ISOCAM in the 5-8.5{mu}m passband, comes from the photodissociation region at the periphery of the ionized gas. B2 is an ultracompact HII region whose exciting star, probably of spectral type later than B0.5V, is not detected; this indicates a visual extinction greater than 60mag. A very steep and regular increase of the extinction from west to east is observed over the whole of Sh2-88B.
- ID:
- ivo://CDS.VizieR/J/MNRAS/390/1185
- Title:
- JHK photometry in 2 star-forming regions
- Short Name:
- J/MNRAS/390/1185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- IRAS 21413+5442 and IRAS 21407+5441 are two massive star-forming regions of high luminosity, likely associated with each other. Near-infrared (NIR) photometry on these two IRAS sources was performed at United Kingdom Infrared Telescope (UKIRT) using the UFTI under excellent seeing conditions yielding an angular resolution of ~0.5arcsec. Our results reveal details of stellar content to a completeness limit (90 per cent) of J=18.5, H=18.0 and K=17.5mag in the two regions. In IRAS 21413+5442, we identify a late O-type star, having large H-K colour, to be near the centre of the CO jets observed by earlier authors. The UKIRT images reveal in IRAS 21407+5441, a faint but clear compact HII region around a central high- and intermediate-mass star cluster. We have detected a number of sources with large H-K colour which are not detected in J band. We also present the GMRT radio continuum map at 1.28GHz covering the entire region surrounding the two star-forming clouds.
- ID:
- ivo://CDS.VizieR/J/AJ/131/951
- Title:
- JHK photometry in the direction of RCW 121
- Short Name:
- J/AJ/131/951
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report near-infrared (NIR) broadband and narrowband photometric observations in the direction of the IRAS 17149-3916 source that reveal the presence of a young cluster of massive stars embedded in an HII region coincident with RCW 121. These observations, together with published radio data and Midcourse Space Experiment and Spitzer images, were used to determine some of the physical parameters of the region. We found 96 cluster member candidates in an area of about 1.5x2.0arcmin^2^, 30% of them showing excess emission in the near-IR.
- ID:
- ivo://CDS.VizieR/J/ApJ/602/850
- Title:
- JHK' photometry near IRAS 18507+0121
- Short Name:
- J/ApJ/602/850
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have observed the massive star-forming region IRAS 18507+0121 at millimeter wavelengths in 3mm continuum emission, H^13^CO+ (J=1-0) and SiO (v=0,J=2-1) line emission, and at near-infrared (NIR) wavelengths between 1.2 and 2.1{mu}m. Two compact molecular cores are detected: one north and one south, separated by ~40". The northern molecular core contains a newly discovered, deeply embedded, B2 protostar surrounded by several hundred solar masses of warm gas and dust, G34.4+0.23 MM. Based on the presence of warm dust emission and the lack of detection at NIR wavelengths, we suggest that G34.4+0.23 MM may represent the relatively rare discovery of a massive protostar (e.g., analogous to a low-mass "Class 0" protostar). The southern molecular core is associated with an NIR cluster of young stars and an ultracompact HII region, G34.4+0.23, with a central B0.5 star. The fraction of NIR stars with excess infrared emission indicative of circumstellar material is greater than 50%, which suggests an upper limit on the age of the IRAS 18507+0121 star-forming region of 3Myr.
- ID:
- ivo://CDS.VizieR/J/A+A/464/909
- Title:
- JHK photometry near IRAS 06145+1455
- Short Name:
- J/A+A/464/909
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our goal in this paper is to study stars and molecular gas in the direction of IRAS 06145+1455 (WB89-789). The kinematic distance of the associated molecular cloud is 11.9kpc. With a galactocentric distance of ~20.2kpc, this object is at the edge of the (molecular) disk of the Galaxy. We use near-IR (J, H, K), molecular line-, and dust continuum observations.
- ID:
- ivo://CDS.VizieR/J/AJ/121/3160
- Title:
- JHK photometry near the Trapezium region
- Short Name:
- J/AJ/121/3160
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of J, H, and Ks time-series photometry obtained with the southern 2MASS telescope over a 0.84{deg}x6{deg} region centered near the Trapezium region of the Orion Nebula cluster. These data are used to establish the near-infrared variability properties of premain-sequence stars in Orion on timescales of ~1-36days, ~2 months, and ~2 years. A total of 1235 near-infrared variable stars are identified, ~93% of which are likely associated with the Orion A molecular cloud.
- ID:
- ivo://CDS.VizieR/J/A+A/429/115
- Title:
- JHK' photometry of Blue Compact Dwarf Galaxies
- Short Name:
- J/A+A/429/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is part of a series of publications which present a systematic study of Blue Compact Dwarf (BCD) Galaxies in the near infrared (NIR). Compared to the visible light, NIR data allow a better separation of the starburst emission from the light distribution of the old stellar low-surface brightness (LSB) host galaxy. We analyze deep NIR broad band images of a sample of 11 BCDs, observed with the Calar Alto 3.6m telescope. This work enlarges the samples presented in preceding papers of this study (Noeske et al., 2003A&A...410..481N, Cairos et al., 2003ApJ...593..312C) by BCDs of the most common morphological type, displaying a regular elliptical LSB host galaxy. The data presented here allow the detection and quantitative study of the extended stellar LSB host galaxy in all sample BCDs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/361/211
- Title:
- JHK photometry of brown dwarfs in Orion
- Short Name:
- J/MNRAS/361/211
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a deep near-infrared (JHK) survey of the outer parts of the Trapezium Cluster with Gemini South/Flamingos. 396 sources were detected in a 26-arcmin^2^ area, including 138 brown dwarf candidates, defined as M<0.075M_{sun}_ for an assumed age of 1Myr. Only 33 of the brown dwarf candidates are planetary mass candidates with estimated masses in the range 0.003<M<0.012M_{sun}_. In an extinction-limited sample (AV<5) complete to approximately 0.005M_{sun}_ (5M_Jup_) the mass function appears to drop by a factor of 2 at the deuterium burning threshold, i.e. at planetary masses. After allowing for background contamination it is likely that planetary mass objects at 3-13M_Jup_ number <10% of the cluster population, with an upper limit of 13%. Analysis of the spatial distribution of stars and brown dwarf candidates suggests that brown dwarfs and very low-mass stars (M<0.1M_{sun}_) are less likely than more massive stars to have wide (>150AU) binary companions.
- ID:
- ivo://CDS.VizieR/J/A+A/525/A1
- Title:
- JHK photometry of CBJC 8 sources
- Short Name:
- J/A+A/525/A1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The infrared cluster CBJC 8 is associated with a 6.7GHz methanol maser and a compact radio-continuum source, G85.40-0.00. It is located at a distance of about 8kpc. The aim is to study the characteristics of this distant and compact embedded cluster and derive the properties of its stellar population. We present new ground-based near- and mid-imaging observations of this region. The calibrated images were analysed together with archive Spitzer IRAC images. Based on the discovery of a considerable fraction of embedded sources with infrared excess emission that are concentrated within a radius around 16arcsec centred near the position of the compact HII region G85.40-0.00, we were able to confirm the presence of a very young embedded cluster. It was found to contain more than 58 members brighter than M_K_=2.6, with two-thirds of them showing significant near- or mid-IR excess emission. Spectral energy distributions and extrapolated total luminosities are presented for nine sources with large mid-infrared excesses that were measured in all four IRAC bands. For the brightest of these, G8540A, which is associated with a methanol maser and a compact HII region, we fitted a model of an infalling envelope plus disc plus central star to its observed 1.6 to 850um fluxes to get an idea of its physical properties. We also report the presence of a single 2.12um molecular hydrogen line emission knot near the centre of the cluster, suggesting the outflow activity.
