- ID:
- ivo://CDS.VizieR/J/A+A/550/A83
- Title:
- NIR observations of CG1 and CG2
- Short Name:
- J/A+A/550/A83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Cometary globules CG1 and CG2 are "classical" cometary globules in the Gum Nebula region at a distance of ~300pc. The objective of this study is to examine the mass distribution and the structure of CG1 and CG2 through extinction, and to study the star formation activity in CG1 and CG2. The NIR JHKs photometry is used in creating visual extinction maps.
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- ID:
- ivo://CDS.VizieR/J/ApJ/867/79
- Title:
- NIR observations of GF 9/LDN 1082C field stars
- Short Name:
- J/ApJ/867/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The orientation of the magnetic field (B field) in the filamentary dark cloud GF 9 was traced from the periphery of the cloud into the L1082C dense core that contains the low-mass, low-luminosity Class 0 young stellar object (YSO) GF 9-2 (IRAS 20503+6006). This was done using SOFIA HAWC+ dust thermal emission polarimetry (TEP) at 216{mu}m in combination with Mimir near-infrared background starlight polarimetry (BSP) conducted in the H band (1.6{mu}m) and K band (2.2{mu}m). These observations were augmented with published I-band (0.77{mu}m) BSP and Planck 850{mu}m TEP to probe B-field orientations with offset from the YSO in a range spanning 6000au to 3pc. No strong B-field orientation change with offset was found, indicating remarkable uniformity of the B-field from the cloud edge to the YSO environs. This finding disagrees with weak-field models of cloud core and YSO formation. The continuity of inferred B-field orientations for both TEP and BSP probes is strong evidence that both are sampling a common B field that uniformly threads the cloud, core, and YSO region. Bayesian analysis of Gaia DR2 stars matched to the Mimir BSP stars finds a distance to GF 9 of 270+/-10pc. No strong wavelength dependence of B-field orientation angle was found, contrary to previous claims.
- ID:
- ivo://CDS.VizieR/J/A+A/499/483
- Title:
- NIR observations of sources in galactic center
- Short Name:
- J/A+A/499/483
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a study that uses AO assisted observations obtained at the ESO VLT in the NIR H-band and 7 intermediate bands covering the NIR K-band. A comparison of the resulting SEDs with a blackbody of variable extinction then allows us to determine the presence and strength of a CO absorption feature to distinguish between early and late type stars. This new method is suitable for classifying K giants (and later), as well as B2 main sequence (and earlier) stars that are brighter than 15.5mag in the K band in the central parsec. Extremely red objects and foreground sources can also be reliably removed from the sample. Several results, such as the shape of the KLF and the spatial distribution of both early and late type stars, confirm and extend previous works. The distribution of the early type stars can be fitted with a steep power law (beta_1"_=-1.49+/-0.12), alternatively with a broken power law, beta_1-10"_=-1.08+/-0.12, beta_10-20"_=-3.46+/-0.58, since we find a drop in the early type density at ~10". We also detect early type candidates outside of 0.5pc in significant numbers for the first time. The late type density function shows an inversion in the inner 6", with a power-law slope of beta_R<6"_=0.17+/-0.09. The late type KLF has a power-law slope of 0.30+/-0.01, closely resembling the KLF obtained for the bulge of the Milky Way. The early type KLF has a much flatter slope of (0.14+/-0.02). Our results agree best with an in-situ star formation scenario.
- ID:
- ivo://CDS.VizieR/J/A+A/511/A18
- Title:
- NIR observations of stars near SgrA*
- Short Name:
- J/A+A/511/A18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The nuclear star cluster of the Galaxy is an important template for understanding its extragalactic counterparts, which can currently not be resolved into individual stars. Important drawbacks of observations of the Galactic center are, however, the presence of strong and spatially highly variable interstellar extinction and extreme crowding of the sources, which makes the use of adaptive optics techniques necessary. Both points pose serious obstacles to precise photometry that is needed for analyzing the stellar population. The aims of this work are to provide accurate photometry in multiple near-infrared broadband filters, to determine the power-law index of the extinction-law toward the central parsec of the Galaxy, to provide measurements of the absolute extinction toward the Galactic center, and finally to measure the spatial variability of extinction on arcsecond scales.
- ID:
- ivo://CDS.VizieR/J/ApJ/901/L7
- Title:
- NIR obs. of the Gal. magnetar SGR 1935+215 with PGIR
- Short Name:
- J/ApJ/901/L7
- Date:
- 23 Feb 2022 09:05:54
- Publisher:
- CDS
- Description:
- The Galactic magnetar SGR 1935+2154 has been reported to produce the first example of a bright millisecond-duration radio burst (FRB200428) similar to the cosmological population of fast radio bursts (FRBs). The detection of a coincident bright X-ray burst represents the first observed multiwavelength counterpart of an FRB. However, the search for similar emission at optical wavelengths has been hampered by the high inferred extinction on the line of sight. Here, we present results from the first search for second-timescale emission from the source at near-infrared (NIR) wavelengths using the Palomar Gattini-IR observing system in the J band, enabled by a novel detector readout mode that allows short exposure times of ~0.84s with 99.9% observing efficiency. With a total observing time of ~12hr (~47728 images) during its 2020 outburst, we place median 3{sigma} limits on the second-timescale NIR fluence of <~18Jy.ms (13.1 AB mag). The corresponding extinction-corrected limit is <~125Jy.ms for an estimated extinction of A_J_=2.0mag. Our observations were sensitive enough to easily detect an NIR counterpart of FRB 200428 if the NIR emission falls on the same power law as observed across its radio to X-ray spectrum. We report nondetection limits from epochs of four simultaneous X-ray bursts detected by the Insight-HXMT and NuSTAR telescopes during our observations. These limits provide the most stringent constraints to date on fluence of flares at ~10^14^Hz, and constrain the fluence ratio of the NIR emission to coincident X-ray bursts to R_NIR_<~0.025 (fluence index >~0.35).
- ID:
- ivo://CDS.VizieR/J/ApJS/239/22
- Title:
- NIR obs. of X-ray AGNs in COSMOS, SXDS & E-CDF-S
- Short Name:
- J/ApJS/239/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-IR spectroscopy in the J- and H-bands for a large sample of 243 X-ray-selected, moderate-luminosity Type 1 active galactic nuclei (AGNs) in the COSMOS, SXDS, and E-CDF-S survey fields using the multi-object spectrograph Subaru/FMOS. Our sample covers the redshift range 0.5<=z<=3.0 and X-ray luminosity range of 10^43^<=L_[2-10keV]_<=10^45^erg/s. We provide emission-line properties and derived virial black hole mass estimates, bolometric luminosities, and Eddington ratios, based on H{alpha} (211), H{beta} (63), and MgII (4). We compare line widths, luminosities, and black hole mass estimates from H{alpha} and H{beta}, and augment these with commensurate measurements of MgII and CIV detected in optical spectra. We demonstrate the robustness of using H{alpha}, H{beta}, and MgII as reliable black hole mass estimators for high-z moderate-luminosity AGNs, while the use of CIV is prone to large uncertainties (>=0.4dex). We extend a recently proposed correction based on the CIV blueshift to lower luminosities and black hole masses. While our sample shows an improvement in their CIV black hole mass estimates, the deficit of high blueshift sources reduces its overall importance for moderate-luminosity AGNs compared to the most luminous quasars. In addition, we revisit luminosity correlations between Lbol, L_[2-10keV]_, L[OIII], L5100, and LH{alpha} and find them to be consistent with a simple empirical model, based on a small number of well-established scaling relations. Finally, we highlight our highest redshift AGN, CID 781, at z=4.6, which has the lowest black hole mass (~10^8^M_{sun}_) among current near-IR samples at this redshift and is in a state of fast growth.
- ID:
- ivo://CDS.VizieR/J/AJ/117/2980
- Title:
- NIR photometric studies of R Canis Majoris
- Short Name:
- J/AJ/117/2980
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here the first light curves of the peculiar Algol binary system R Canis Majoris obtained in the near-infrared photometric bands J and K. The light curves are fitted for a semidetached model with the Wilson-Devinney light-curve synthesis program. Five epochs of primary minima and four epochs of secondary minima are obtained in the present study. The increased depth of the secondary minima in the near-IR bands compared with the optical bands enabled us to determine the moments of secondary minima with nearly the same accuracy as those of primary minima. All the secondary minima appear at phase 0.5, and the durations are equal for the primary and the secondary eclipses. The epochs of primary minima follow the nearly sinusoidal O-C curve that has been observed for this star in previous studies. The values of O-C for the secondary minima were in the same range as those of the primary minima observed by us.
- ID:
- ivo://CDS.VizieR/J/ApJ/741/35
- Title:
- NIR photometry and polarization in NGC 2264
- Short Name:
- J/ApJ/741/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Near-infrared imaging polarimetry in the J, H, and Ks bands has been carried out for the protostellar cluster region around NGC 2264 IRS 2 in the Monoceros OB1 molecular cloud. Various infrared reflection nebula clusters (IRNCs) associated with NGC 2264 IRS 2 and the IRAS 12 S1 core, as well as local infrared reflection nebulae (IRNe), were detected. The illuminating sources of the IRNe were identified with known or new near- and mid-infrared sources. In addition, 314 point-like sources were detected in all three bands and their aperture polarimetry was studied. Using a color-color diagram, reddened field stars and diskless pre-main-sequence stars were selected to trace the magnetic field (MF) structure of the molecular cloud. The mean polarization position angle of the point-like sources is 81+/-29{deg} in the cluster core, and 58+/-24{deg} in the perimeter of the cluster core, which is interpreted as the projected direction on the sky of the MF in the observed region of the cloud. The Chandrasekhar-Fermi method gives a rough estimate of the MF strength to be about 100uG. A comparison with recent numerical simulations of the cluster formation implies that the cloud dynamics is controlled by the relatively strong MF. The local MF direction is well associated with that of CO outflow for IRAS 12 S1 and consistent with that inferred from submillimeter polarimetry. In contrast, the local MF direction runs roughly perpendicular to the Galactic MF direction.
- ID:
- ivo://CDS.VizieR/J/A+A/542/A39
- Title:
- NIR photometry in 10 nearby spiral galaxies
- Short Name:
- J/A+A/542/A39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spiral structure is a prominent feature in many disk galaxies and is often outlined by bright, young objects. We study the distribution of young stellar clusters in grand-design spiral galaxies and thereby determine whether strong spiral perturbations can influence star formation.
- ID:
- ivo://CDS.VizieR/J/AJ/160/35
- Title:
- NIR photometry in the T Tauri system with Keck
- Short Name:
- J/AJ/160/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from adaptive optics imaging of the T Tauri triple system obtained at the Keck and Gemini Observatories in 2015-2019. We fit the orbital motion of T Tau Sb relative to Sa and model the astrometric motion of their center of mass relative to T Tau N. Using the distance measured by Gaia, we derived dynamical masses of M_Sa_=2.05{+/-}0.14M_{sun}_ and M_Sb_=0.43{+/-}0.06M_{sun}_. The precision in the masses is expected to improve with continued observations that map the motion through a complete orbital period; this is particularly important as the system approaches periastron passage in 2023. Based on published properties and recent evolutionary tracks, we estimate a mass of ~2M_{sun}_ for T Tau N, suggesting that T Tau N is similar in mass to T Tau Sa. Narrowband infrared photometry shows that T Tau N remained relatively constant between late 2017 and early 2019 with an average value of K=5.54{+/-}0.07mag. Using T Tau N to calibrate relative flux measurements since 2015, we found that T Tau Sa varied dramatically between 7.0 and 8.8mag in the K band over timescales of a few months, while T Tau Sb faded steadily from 8.5 to 11.1mag in the K band. Over the 27yr orbital period of the T Tau S binary, both components have shown 3-4mag of variability in the K band, relative to T Tau N.
