- ID:
- ivo://CDS.VizieR/J/MNRAS/384/675
- Title:
- Monitoring low-mass stars in NGC 2362
- Short Name:
- J/MNRAS/384/675
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the results of a time-series photometric survey of NGC 2362, carried out using the CTIO 4-m Blanco telescope and Mosaic-II detector as part of the Monitor project. Rotation periods were derived for 271(*) candidate cluster members over the mass range 0.1~<M/M_{sun}_<~1.2. The rotation period distributions show a clear mass-dependent morphology, qualitatively similar to that in NGC 2264, as would be expected from the age of this cluster. Using models of angular momentum evolution, we show that angular momentum losses over the ~1-5Myr age range appear to be needed in order to reproduce the evolution of the slowest rotators in the sample from the ONC to NGC 2362, as found by many previous studies. By incorporating Spitzer IRAC mid-infrared (mid-IR) measurements, we found that three to four objects showing mid-IR excesses indicative of the presence of circumstellar discs were all slow rotators, as would be expected in the disc regulation paradigm for early pre-main-sequence angular momentum evolution, but this result is not statistically significant at present, given the extremely limited sample size. (*) The abstract indicates 271 clusters, but the actual number is 272.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/369/57
- Title:
- Monitoring Mkn 279 in BVRI and H{beta} fluxes
- Short Name:
- J/A+A/369/57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Mid-infrared images of the Seyfert 1 galaxy Mrk 279 obtained with the ISO satellite are presented together with the results of a one-year monitoring campaign of the 2.5-11.7{mu}m spectrum. Contemporaneous optical photometric and spectrophotometric observations are also presented. The galaxy appears as a point-like source at the resolution of the ISOCAM instrument (4-5"). The 2.5-11.7{mu}m average spectrum of the nucleus in Mrk 279 shows a strong power law continuum with {alpha}=-0.80+/-0.05 (F_{nu}_{prop.to}{nu}^{alpha}^) and weak PAH emission features. The Mrk 279 spectral energy distribution shows a mid-IR bump, which extends from 2 to 15-20{mu}m. The mid-IR bump is consistent with thermal emission from dust grains at a distance of >100 light-days. No significant variations of the mid-IR flux have been detected during our observing campaign, consistent with the relatively low amplitude (~10% rms) of the optical variability during the campaign. The time delay for H{beta} line emission in response to the optical continuum variations is {tau}=16.7^+5.3^_-5.6_days, consistent with previous measurements.
- ID:
- ivo://CDS.VizieR/J/AJ/147/82
- Title:
- Monitoring of disk-bearing stars in NGC 2264
- Short Name:
- J/AJ/147/82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Coordinated Synoptic Investigation of NGC 2264, a continuous 30 day multi-wavelength photometric monitoring campaign on more than 1000 young cluster members using 16 telescopes. The unprecedented combination of multi-wavelength, high-precision, high-cadence, and long-duration data opens a new window into the time domain behavior of young stellar objects. Here we provide an overview of the observations, focusing on results from Spitzer and CoRoT. The highlight of this work is detailed analysis of 162 classical T Tauri stars for which we can probe optical and mid-infrared flux variations to 1% amplitudes and sub-hour timescales. We present a morphological variability census and then use metrics of periodicity, stochasticity, and symmetry to statistically separate the light curves into seven distinct classes, which we suggest represent different physical processes and geometric effects. We provide distributions of the characteristic timescales and amplitudes and assess the fractional representation within each class. The largest category (>20%) are optical "dippers" with discrete fading events lasting ~1-5 days. The degree of correlation between the optical and infrared light curves is positive but weak; notably, the independently assigned optical and infrared morphology classes tend to be different for the same object. Assessment of flux variation behavior with respect to (circum)stellar properties reveals correlations of variability parameters with H{alpha} emission and with effective temperature. Overall, our results point to multiple origins of young star variability, including circumstellar obscuration events, hot spots on the star and/or disk, accretion bursts, and rapid structural changes in the inner disk.
- ID:
- ivo://CDS.VizieR/J/ApJ/873/117
- Title:
- Monitoring of the double quasar SDSS J1442+4055
- Short Name:
- J/ApJ/873/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present r-band photometric monitoring of the two images, A and B, of the gravitationally lensed quasar SDSS J1442+4055 using the Liverpool Telescope (LT). From the LT light curves between 2015 December and 2018 August, we derive at once a time delay of 25.0+/-1.5d (1{sigma} confidence interval; A is leading) and microlensing magnification gradients below 10^-4^mag/d. The delay interval is not expected to be affected by an appreciable microlensing-induced bias, so it can be used to estimate cosmological parameters. This paper also focuses on new Gran Telescopio Canarias (GTC) and LT spectroscopic observations of the lens system. We determine the redshift of two bright galaxies around the doubly imaged quasar using LT spectroscopy, while GTC data lead to low-noise individual spectra of A, B, and the main lensing galaxy, G1. The G1 spectral shape is accurately matched to an early-type galaxy template at z=0.284, and it has potential for further relevant studies. Additionally, the quasar spectra show absorption by metal-rich gas at z~2. This dusty absorber is responsible for an extinction bump at a rest-frame wavelength of 2209+/-2{AA}, which has strengths of ~0.47 and 0.76mag/{mu}m for A and B, respectively. In such an intervening system, the dust-to-gas ratio, gas-phase metallicity indicator [Zn/H], and dust depletion level [Fe/Zn] are relatively high.
- ID:
- ivo://CDS.VizieR/J/ApJ/754/101
- Title:
- Monoceros Overdensity deep imaging with Subaru
- Short Name:
- J/ApJ/754/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive distance, density, and metallicity distribution of the stellar Monoceros Overdensity (MO) in the outer Milky Way, based on deep imaging with the Subaru Telescope. We applied color-magnitude diagram fitting techniques in three stripes at galactic longitudes, l~130{deg}, 150{deg}, 170{deg}, and galactic latitudes, +15{deg}<=b<=+25{deg}. The MO appears as a wall of stars at a heliocentric distance of ~10.1+/-0.5kpc across the observed longitude range with no distance change. The MO stars are more metal-rich ([Fe/H]~-1.0) than the nearby stars at the same latitude. These data are used to test three different models for the origin of the MO: a perturbed disk model, which predicts a significant drop in density adjacent to the MO that is not seen; a basic flared disk model, which can give a good match to the density profile but the MO metallicity implies the disk is too metal-rich to source the MO stars; and a tidal stream model, which, from the literature, brackets the distances and densities we derive for the MO, suggesting that a model can be found that would fully fit the MO data. Further data and modeling will be required to confirm or rule out the MO feature as a stream or as a flaring of the disk.
- ID:
- ivo://CDS.VizieR/J/AJ/140/533
- Title:
- Morphologies of selected AGN
- Short Name:
- J/AJ/140/533
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the optical morphologies of candidate active galaxies identified at radio, X-ray, and mid-infrared wavelengths. We use the Advanced Camera for Surveys General Catalog (ACS-GC) to identify 372, 1360, and 1238 active galactic nucleus (AGN) host galaxies from Very Large Array, XMM-Newton, and Spitzer Space Telescope observations of the COSMOS field, respectively. We investigate both quantitative (GALFIT) and qualitative (visual) morphologies of these AGN host galaxies, split by brightness in their selection band.
- ID:
- ivo://CDS.VizieR/J/MNRAS/444/3015
- Title:
- Morphologies of S4G galaxies
- Short Name:
- J/MNRAS/444/3015
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue and images of visually detected features, such as asymmetries, extensions, warps, shells, tidal tails, polar rings, and obvious signs of mergers or interactions, in the faint outer regions (at and outside of R_25_) of nearby galaxies. This catalogue can be used in future quantitative studies that examine galaxy evolution due to internal and external factors. We are able to reliably detect outer region features down to a brightness level of 0.03MJy/sr/pixel at 3.6{mu}m in the Spitzer Survey of Stellar Structure in Galaxies (S4G). We also tabulate companion galaxies. We find asymmetries in the outer isophotes in 22+/-1% of the sample. The asymmetry fraction does not correlate with galaxy classification as an interacting galaxy or merger remnant, or with the presence of companions. We also compare the detected features to similar features in galaxies taken from cosmological zoom re-simulations. The simulated images have a higher fraction (33%) of outer disc asymmetries, which may be due to selection effects and an uncertain star formation threshold in the models. The asymmetries may have either an internal (e.g. lopsidedness due to dark halo asymmetry) or external origin.
- ID:
- ivo://CDS.VizieR/J/AJ/146/151
- Title:
- Morphology catalog of nearby galaxies from SDSS DR7
- Short Name:
- J/AJ/146/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the statistical properties of a volume-limited sample of 7429 nearby (z=0.033-0.044) galaxies from the Sloan Digital Sky Survey Data Release 7. Our database includes morphology distribution as well as the structural and spectroscopic properties of each morphology type based on the recent remeasurements of spectral line strengths by Oh and collaborators. Our database does not include galaxies that are apparently smaller and flatter because morphology classification of them turned out to be difficult. Our statistics confirmed the up-to-date knowledge of galaxy populations, e.g., correlations between morphology and line strengths as well as the derived ages. We hope that this database will be useful as a reference.
- ID:
- ivo://CDS.VizieR/J/ApJ/652/1068
- Title:
- Morphology of cool and warm infrared galaxies
- Short Name:
- J/ApJ/652/1068
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have analyzed a sample of nearby cool and warm infrared (IR) galaxies using photometric and structural parameters. The set of measures include far-infrared color [C=log(S_60um_/S_100um_)], total IR luminosity (L_FIR_), radio surface brightness, and radio, near-infrared, and optical sizes.
- ID:
- ivo://CDS.VizieR/J/ApJS/125/349
- Title:
- Morphology of 12micron Seyfert Galaxies
- Short Name:
- J/ApJS/125/349
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 263 optical and near-infrared (NIR) images for 42 1s and 48 Seyfert 2s, selected from the Extended 12{mu}m Galaxy Sample. Elliptically averaged profiles are derived from the images, and isophotal radii and magnitudes are calculated from these. We also report virtual aperture photometry that, judging from comparison with previous work, is accurate to roughly 0.05 mag in the optical, and 0.07 mag in the NIR. Our B-band isophotal magnitude and radii, obtained from ellipse fitting, are in good agreement with those of Third Reference Catalogue of Bright Galaxies. When compared with the B band, V, I, J, and K isophotal diameters show that the colors in the outer regions of Seyfert galaxies are consistent with the colors of normal spirals. Differences in the integrated isophotal colors and comparison with a simple model show that the active nucleus+bulge are stronger and redder in the NIR than in the optical. Finally, roughly estimated Seyfert disk surface brightnesses are significantly brighter in B and K than those in normal spirals of similar morphological type.
