- ID:
- ivo://CDS.VizieR/J/A+A/486/453
- Title:
- NIR photometry of early-type stars in Cyg OB2
- Short Name:
- J/A+A/486/453
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Cygnus OB2 is one of the richest OB associations in the local Galaxy, and is located in a vast complex containing several other associations, clusters, molecular clouds, and HII regions. However, the stellar content of Cygnus OB2 and its surroundings remains rather poorly known largely due to the considerable reddening in its direction at visible wavelength. We investigate the possible existence of an extended halo of early-type stars around Cygnus OB2, which is hinted at by near-infrared color-color diagrams, and its relationship to Cygnus OB2 itself, as well as to the nearby association Cygnus OB9 and to the star forming regions in the Cygnus X North complex. Candidate selection is made with photometry in the 2MASS all-sky point source catalog. The early-type nature of the selected candidates is confirmed or discarded through our infrared spectroscopy at low resolution. In addition, spectral classifications in the visible are presented for many lightly-reddened stars.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/552/A74
- Title:
- NIR photometry of Galactic PNe with VVV Survey
- Short Name:
- J/A+A/552/A74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Aperture photometry of known PNe in the VVV area was retrieved from source catalogues. 579 PNe were selected from the VVV (VISTA Variables in the Via Lactea) survey catalogue. Of these 353 present near-infrared photometry, 75 are highly extended sources, and 123 PNe could not be related to any source in the VVV images, the remainder are sources which NIR emission of the PN is detected in the frames, but there are no photometric data in the VSA database.
- ID:
- ivo://CDS.VizieR/J/ApJ/804/27
- Title:
- NIR photometry of hot dust-obscured galaxies
- Short Name:
- J/ApJ/804/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Wide-field Infrared Survey Explorer (WISE) mission has unveiled a rare population of high-redshift (z=1-4.6), dusty, hyper-luminous galaxies, with infrared luminosities L_IR_>10^13^L_{sun}_, and sometimes exceeding 10^14^L_{sun}_. Previous work has shown that their dust temperatures and overall far-infrared spectral energy distributions (SEDs) are significantly hotter than expected to be powered by star formation. We present here an analysis of the rest-frame optical through mid-infrared SEDs for a large sample of these so-called "hot, dust-obscured galaxies" (Hot DOGs).
- ID:
- ivo://CDS.VizieR/J/A+A/489/229
- Title:
- NIR photometry of IRAS 19410+2336
- Short Name:
- J/A+A/489/229
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- IRAS 19410+2336 is a young massive star forming region with an intense outflow activity. Outflows are frequently studied in the near-infrared (NIR) since the H_2_ emission in this wavelength range often traces the shocked molecular gas. However, the mechanisms behind the H_2_ emission detected in IRAS 19410+2336 have not been clarified yet. We present here spatially resolved NIR spectroscopy which allows us to verify whether the H_2_ emission originates from thermal emission in shock fronts or from fluorescence excitation by non-ionizing UV photons. Moreover, NIR spectroscopy also offers the possibility of studying the characteristics of the putative driving source(s) of the H_2_ emission by the detection of photospheric and circumstellar spectral features, and of the environmental conditions (e.g. extinction). We obtained long-slit, intermediate-resolution, NIR spectra of IRAS 19410+2336 using LIRIS, the NIR imager/spectrographer mounted on the 4.2m William Herschel Telescope. As a complement, we also obtained J, H and Ks images with the Las Campanas 2.5m Du Pont Telescope, and archival mid-infrared (MIR) Spitzer-images at 3.6, 4.5, 5.8 and 8.0um.
- ID:
- ivo://CDS.VizieR/J/A+AS/126/479
- Title:
- NIR photometry of IRAS sources. III
- Short Name:
- J/A+AS/126/479
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the near infrared photometry of a new sample of 225 IRAS sources, many of them previously unidentified in the literature, selected because their far infrared colours are similar to those shown by known planetary nebulae. The results obtained are used to establish the main source of near infrared emission. Combining this information with the far infrared IRAS data and a few additional criteria we determine the nature and evolutionary stage of all the sources observed so far, including those for which near infrared photometry was previously reported in Papers I (Manchado et al., 1989A&A...214..139M) and II (Garcia-Lario et al., 1990A&AS...82..497G).
- ID:
- ivo://CDS.VizieR/J/AJ/143/43
- Title:
- NIR photometry of NGC 604 star-forming region
- Short Name:
- J/AJ/143/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a near-infrared study focused on the detection and characterization of the youngest stellar component of the NGC 604 giant star-forming region in the Triangulum galaxy (M 33). By means of color-color diagrams derived from the photometry of JHK_s_ images taken with the Gemini Near Infrared Imaging and Spectrometer (NIRI), we have found 68 candidate massive young stellar objects. The spatial distribution of these sources matches the areas where previous studies suggested that star formation might be taking place, and the high spatial resolution of our deep NIRI imaging allows us to pinpoint the star-forming knots. An analysis of the fraction of objects that show infrared excess suggests that the star formation is still active, supporting the presence of a second generation of stars being born, although the evidence for or against sequential star formation does not seem to be conclusive.
- ID:
- ivo://CDS.VizieR/J/AJ/154/263
- Title:
- NIR photometry of 77 RR Lyrae stars
- Short Name:
- J/AJ/154/263
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained single-phase near-infrared (NIR) magnitudes in the J and K bands for 77 RR Lyrae (RRL) stars in the Fornax Dwarf Spheroidal Galaxy. We have used different theoretical and empirical NIR period-luminosity-metallicity calibrations for RRL stars to derive their absolute magnitudes, and found a true, reddening-corrected distance modulus of 20.818+/-0.015(statistical)+/-0.116(systematic) mag. This value is in excellent agreement with the results obtained within the Araucaria Project from the NIR photometry of red clump stars (20.858+/-0.013 mag), the tip of the red giant branch (20.84+/-0.04+/-0.14 mag), as well as with other independent distance determinations to this galaxy. The effect of metallicity and reddening is substantially reduced in the NIR domain, making this method a robust tool for accurate distance determination at the 5% level. This precision is expected to reach the level of 3% once the zero points of distance calibrations are refined thanks to the Gaia mission. NIR period-luminosity-metallicity relations of RRL stars are particularly useful for distance determinations to galaxies and globular clusters up to 300 kpc, that lack young standard candles, like Cepheids.
- ID:
- ivo://CDS.VizieR/J/MNRAS/384/1502
- Title:
- NIR photometry of X-ray luminous BCGs
- Short Name:
- J/MNRAS/384/1502
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the near-infrared evolution of brightest cluster galaxies (BCGs) from a sample of rich galaxy clusters since z~1. By employing an X-ray selection of LX>10^44^erg/s, we limit environmental effects by selecting BCGs in comparably high-density regions. We find a positive relationship between X-ray and near-infrared luminosity for BCGs in clusters with LX>5x10^44^erg/s. Applying a correction for this relation, we reduce the scatter in the BCG absolute magnitude by a factor of 30 per cent. The near-infrared J-K colour evolution demonstrates that the stellar population in BCGs has been in place since at least z=2, and that we expect a shorter period of star formation than that predicted by current hierarchical merger models. We also confirm that there is a relationship between 'blue' J-K colour and the presence of BCG emission lines associated with star formation in cooling flows.
- ID:
- ivo://CDS.VizieR/J/ApJS/211/3
- Title:
- NIR photometry variability in {rho} Oph
- Short Name:
- J/ApJS/211/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Presented are the results of a near-IR photometric survey of 1678 stars in the direction of the {rho} Ophiuchus ({rho} Oph) star forming region using data from the 2MASS Calibration Database. For each target in this sample, up to 1584 individual J-, H-, and Ks-band photometric measurements with a cadence of ~1 day are obtained over three observing seasons spanning ~2.5 yr; it is the most intensive survey of stars in this region to date. This survey identifies 101 variable stars with {Delta}Ks-band amplitudes from 0.044 to 2.31 mag and {Delta}(J-Ks) color amplitudes ranging from 0.053 to 1.47 mag. Of the 72 young {rho} Oph star cluster members included in this survey, 79% are variable; in addition, 22 variable stars are identified as candidate members. Based on the temporal behavior of the Ks time-series, the variability is distinguished as either periodic, long time-scale or irregular. This temporal behavior coupled with the behavior of stellar colors is used to assign a dominant variability mechanism. A new period-searching algorithm finds periodic signals in 32 variable stars with periods between 0.49 to 92 days. The chief mechanism driving the periodic variability for 18 stars is rotational modulation of cool starspots while 3 periodically vary due to accretion-induced hot spots. The time-series for six variable stars contains discrete periodic "eclipse-like" features with periods ranging from 3 to 8 days. These features may be asymmetries in the circumstellar disk, potentially sustained or driven by a proto-planet at or near the co-rotation radius. Aperiodic, long time-scale variations in stellar flux are identified in the time-series for 31 variable stars with time-scales ranging from 64 to 790 days. The chief mechanism driving long time-scale variability is variable extinction or mass accretion rates. The majority of the variable stars (40) exhibit sporadic, aperiodic variability over no discernable time-scale. No chief variability mechanism could be identified for these variable stars.
- ID:
- ivo://CDS.VizieR/J/AJ/153/126
- Title:
- NIR polarimetric study in the LMC N159/N160 field
- Short Name:
- J/AJ/153/126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared polarimetric results for the N159/N160 star-forming complex in the Large Magellanic Cloud with SIRPOL, the polarimeter of the Infrared Survey Facility. We separated foreground sources using their visual extinction derived from near-infrared photometric data. The 45 young stellar candidates and 2 high-excitation blobs were matched with our sources, and 12 of them showed high polarization that did not originate from the interstellar dust. We made a polarimetric catalog of 252, 277, and 89 sources at the J, H, and K_s_ bands, respectively. Based on the ratios of the polarization degree between these bands, we verify that the origin of these polarized sources is the dichroic extinction from the interstellar dust aligned by the magnetic field and that the ratios follow a power-law dependence of P_{lambda}_~{lambda}^-0.9^. The linear polarization vectors projected onto the H{alpha} image of the complex turned out to follow the local magnetic field structure. The vector map overlaid on dust and gas emissions shows the close correlation between the magnetic field structure and surrounding interstellar medium. We suggest that the derived magnetic field structure supports the sequential formation scenario of the complex.
