- ID:
- ivo://CDS.VizieR/J/AJ/109/1131
- Title:
- JHK Photometry in Metal Rich Globulars.
- Short Name:
- J/AJ/109/1131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As a first step in investigating the properties of heavily reddened, metal-rich globular clusters, we present JHK colors and magnitudes for four objects: NGC 5927, NGC 6712, NGC 6838 (M71), and Terzan 2. These data begin near the top of the giant branch (GB) and extend to stars six magnitudes fainter, reaching below the horizontal branch (HB). We use our sample and previously published data for two other clusters, 47 Tucanae and M69, to develop techniques for deriving basic properties such as metallicity and distance modulus from observable parameters of cluster color-magnitude diagrams (CMDs) in the near-IR. We also analyze the horizontal branches of the clusters in an attempt to set constraints on mass loss for first-ascent giants. We find that the slope of the linear fit to the GB stars brighter than the HB can be used to predict metallicity to an accuracy of +/- 0.25 dex for clusters with [Fe/H] between -1.0 and -0.3. There appears to be no significant dependence on [Fe/H] for other reddening-free indices measured from the CMD, including the width of the HB and the separation between the GB and HB at the level of the HB. Using the clusters in our sample that have known distances, we derive a value of <M_K0(HB)> = -1.15 +/- 0.10 for the extinction-corrected absolute K magnitude of the HB. This provides a means of determining the distance to clusters for which only infrared CMDs are available. We derive a distance modulus to Terzan 2 of 14.37 +/- 0.2 which places it within a few hundred parsecs of the galactic center. In the J-H,H-K diagram, Terzan 2 giants are located near the Baade's Window giants rather than in the region populated by nearly all other globular cluster stars. The GB of stars in the field around Terzan 2 has a slope that implies [Fe/H] = +0.1, comparable to that in Baade's Window.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/316/102
- Title:
- JHK Photometry in NGC 6334
- Short Name:
- J/A+A/316/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- JHK imaging photometry is reported of an area of approximately 2'x3' centred on the far infrared source NGC 6334 I with limiting magnitudes J=18.3, H=17.8 and K=16.2. More than 224 sources were detected in K-band, increasing by a factor of more than seven the number of objects found in previous near-IR surveys. Most of the sources are located in an area of about 3500 square arcsec centered around the massive young stellar object Irs1, which ionizes the compact HII region NGC 6334 F. The location of these sources and the analysis of the colour-colour and colour-magnitude diagrams suggest the presence of an embedded and young stellar cluster of size ~70" (0.6pc), and stellar density of about 1200pc^-3^. The star formation efficiency is estimated to be SFE=~0.25. Only a few of the most luminous stars of the cluster were found to show large near-IR excesses but this may be due to the non-detection, at the shortest wavelength, of the majority of the highly reddened cluster members. The extinction of the region is very variable with a maximum of A_V_>70 in Irs2 while the average is <A_V_>=~40. Very close to the position of an H_2_O maser associated with NGC 6334 I(N), a contracting core at an earlier evolutionary stage, we found six very red sources, one of which is a small and diffuse nebula seen only at 2.2{mu}m. Finally, the older and developed HII region NGC 6334 E was found to be probably ionized by a small cluster of at least 12 B0-B0.5 ZAMS stars. For a description of the JHK photometric system, see e.g. <GCPD/09>
- 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>
- 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.
