- ID:
- ivo://CDS.VizieR/VI/112
- Title:
- Optical Imaging of 57 spiral galaxies
- Short Name:
- VI/112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical observations of a sample of 57 spiral galaxies and describe the procedures followed to reduce the data. We have obtained images in the optical B and I broad bands, as well as in H{alpha}, with moderate spatial resolution and across wide enough fields to image the complete disks of the galaxies. In addition, we observed 55 of our sample galaxies in the R and eight in the V band, and imaged a subset through a dedicated narrow continuum filter for the H{alpha} line. We describe the data reduction procedures we developed in the course of this work to register, combine and photometrically calibrate each set of images for an individual galaxy. We describe in some detail the procedure used to subtract the continuum emission from our H{alpha} images. In companion papers, we describe near-infrared imaging of the galaxy sample, and present analyses of disk scale lengths, and of properties of bars, rings, and HII regions in the sample galaxies. The images described here will be made available for use by other researchers through the CDS.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/130/1345
- Title:
- Optical-infrared colors of CORALS QSOs
- Short Name:
- J/AJ/130/1345
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The presence of dust in quasar absorbers, such as damped Ly{alpha} (DLA) systems, may cause the background QSO to appear reddened. We investigate the extent of this potential reddening by comparing the optical-to-infrared colors of QSOs with and without intervening absorbers. Our QSO sample is based on the Complete Optical and Radio Absorption Line System (CORALS) survey of Ellison and coworkers. The CORALS data set consists of 66 radio-selected QSOs at z_em_>=2.2 with complete optical identifications. We have obtained near-simultaneous B- and K-band magnitudes for a subset of the CORALS sample and supplemented our observations with further measurements published in the literature. In total, we have B-K colors for 42 of the 66 QSOs, of which 14 have intervening DLA systems. To account for redshift-related color changes, the B-K colors are normalized using the Sloan Digital Sky Survey QSO composite.
- ID:
- ivo://CDS.VizieR/J/MNRAS/377/1531
- Title:
- Optical & infrared photometry of SN 2004eo
- Short Name:
- J/MNRAS/377/1531
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and infrared observations of the unusual Type Ia supernova (SN) 2004eo. The light curves and spectra closely resemble those of the prototypical SN 1992A, and the luminosity at maximum (M_B_=-19.08) is close to the average for a Type Ia supernova (SN Ia). However, the ejected ^56^Ni mass derived by modelling the bolometric light curve (about 0.45M_{sun}_) lies near the lower limit of the ^56^Ni mass distribution observed in normal SNe Ia. Accordingly, SN 2004eo shows a relatively rapid post-maximum decline in the light curve [{delta}m15(B)true=1.46], small expansion velocities in the ejecta and a depth ratio SiII{lambda}5972/SiII{lambda}6355 similar to that of SN 1992A. The physical properties of SN 2004eo cause it to fall very close to the boundary between the faint, low-velocity gradient and high-velocity gradient subgroups proposed by Benetti et al. Similar behaviour is seen in a few other SNe Ia. Thus, there may in fact exist a few SNe Ia with intermediate physical properties.
- ID:
- ivo://CDS.VizieR/J/MNRAS/238/1171
- Title:
- Optical/IR observ. of Radio Galaxies and QSOs
- Short Name:
- J/MNRAS/238/1171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog reports on an extensive optical and infrared study of the 178 radio sources in the Parkes Selected Regions (S > 100 mJy at 2.7 GHz). CCD observations have resulted in the essential completion (95 percent) of optical identifications and have provided B and R photometry. In addition, K photometry has been completed for four of the six selected regions.
- ID:
- ivo://CDS.VizieR/J/ApJ/664/481
- Title:
- Optical/IR photometry of Collinder 69
- Short Name:
- J/ApJ/664/481
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multiwavelength optical and IR photometry of 170 previously known low-mass stars and brown dwarfs of the 5Myr Collinder 69 cluster ({lambda} Orionis). The new photometry supports cluster membership for most of them, with less than 15% of the previous candidates identified as probable nonmembers. The near-IR photometry allows us to identify stars with IR excesses, and we find that the Class II population is very large, around 25% for stars (in the spectral range M0-M6.5) and 40% for brown dwarfs, down to 0.04M_{sun}_, despite the fact that the H{alpha} equivalent width is low for a significant fraction of them. In addition, there are a number of substellar objects, classified as Class III, that have optically thin disks. The Class II members are distributed in an inhomogeneous way, lying preferentially in a filament running toward the southeast. The IR excesses for the Collinder 69 members range from pure Class II (flat or nearly flat spectra longward of 1um), to transition disks with no near-IR excess but excesses beginning within the IRAC wavelength range, to two stars with excess only detected at 24um. Collinder 69 thus appears to be at an age where it provides a natural laboratory for the study of primordial disks and their dissipation.
- ID:
- ivo://CDS.VizieR/J/ApJ/806/258
- Title:
- Optical LCs of QSO J0924+0219 lensed quasar
- Short Name:
- J/ApJ/806/258
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze the optical, UV, and X-ray microlensing variability of the lensed quasar SDSS J0924+0219 using six epochs of Chandra data in two energy bands (spanning 0.4-8.0keV, or 1-20keV in the quasar rest frame), 10 epochs of F275W (rest-frame 1089{AA}) Hubble Space Telescope data, and high-cadence R-band (rest-frame 2770{AA}) monitoring spanning 11 years. Our joint analysis provides robust constraints on the extent of the X-ray continuum emission region and the projected area of the accretion disk. The best-fit half-light radius of the soft X-ray continuum emission region is between 5x10^13^ and 10^15^cm, and we find an upper limit of 10^15^cm for the hard X-rays. The best-fit soft-band size is about 13 times smaller than the optical size, and roughly 7GM_BH_/C^2^ for a 2.8x10^8^M_{sun}_ black hole, similar to the results for other systems. We find that the UV emitting region falls in between the optical and X-ray emitting regions at 10^14^cm<r_1/2.UV_<3x10^15^cm. Finally, the optical size is significantly larger, by 1.5{sigma}, than the theoretical thin-disk estimate based on the observed, magnification-corrected I-band flux, suggesting a shallower temperature profile than expected for a standard disk.
- ID:
- ivo://CDS.VizieR/J/ApJ/856/38
- Title:
- Optical LCs of the counterpart to IC 10 X-2
- Short Name:
- J/ApJ/856/38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an optical and infrared (IR) study of IC 10 X-2, a high-mass X-ray binary in the galaxy IC 10. Previous optical and X-ray studies suggest that X-2 is a Supergiant Fast X-ray Transient: a large-amplitude (factor of ~100), short-duration (hours to weeks) X-ray outburst on 2010 May 21. We analyze R- and g-band light curves of X-2 from the intermediate Palomar Transient Factory taken between 2013 July 15 and 2017 February 14 that show high-amplitude (>~1mag), short-duration (<~8days) flares and dips (>~0.5mag). Near-IR spectroscopy of X-2 from Palomar/TripleSpec show He I, Paschen-{gamma}, and Paschen-{beta} emission lines with similar shapes and amplitudes as those of luminous blue variables (LBVs) and LBV candidates (LBVc). Mid-IR colors and magnitudes from Spitzer/Infrared Array Camera photometry of X-2 resemble those of known LBV/LBVcs. We suggest that the stellar companion in X-2 is an LBV/LBVc and discuss possible origins of the optical flares. Dips in the optical light curve are indicative of eclipses from optically thick clumps formed in the winds of the stellar counterpart. Given the constraints on the flare duration (0.02-0.8 days) and the time between flares (15.1+/-7.8days), we estimate the clump volume filling factor in the stellar winds, f_V_, to be 0.01<f_V_<0.71, which overlaps with values measured from massive star winds. In X-2, we interpret the origin of the optical flares as the accretion of clumps formed in the winds of an LBV/LBVc onto the compact object.
- ID:
- ivo://CDS.VizieR/J/AJ/159/61
- Title:
- Optical LCs & spectrum of the RCB star ZTF18abhjrcf
- Short Name:
- J/AJ/159/61
- Date:
- 07 Mar 2022 07:17:25
- Publisher:
- CDS
- Description:
- R Coronae Borealis stars (RCBs) constitute a rare class of stars that are hydrogen depleted and carbon enriched, possibly from white dwarf mergers. RCBs are identified by their stochastic dimming with photometric variations of as much as eight magnitudes. Hence, the discoveries of RCBs were heavily biased to the limited regions monitored by long-term microlensing experiments. However, recent studies of galactic RCBs have shown that they exhibit distinct mid-infrared colors originating from their cool circumstellar shells. The all-sky Wide-field Infrared Survey Explorer (WISE) survey thus facilitates the identification of RCB candidates. Therefore, combining the WISE colors with large-area time-domain surveys will enable us to discover more RCBs. Here we present the results of a first attempt to identify RCBs in the public Zwicky Transient Facility (ZTF) alert stream, using the alert broker ANTARES. We identify a candidate RCB using the infrared color selection by Tisserand+, 2013A&A...551A..77T and large light curve variations in the optical from ZTF. We then conduct subsequent observations using the FLOYDS spectrograph at the Las Cumbres Observatory and confirm ZTF18abhjrcf as a bona fide RCB. This demonstrates the potential to discover uncharted RCBs as ZTF and other time-domain surveys continue to operate.
- ID:
- ivo://CDS.VizieR/J/A+A/531/A123
- Title:
- Optical light curve of PKS 2155-304
- Short Name:
- J/A+A/531/A123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The long-term optical light curve of PKS 2155-304 is assembled from archival data as well as from so-far unpublished observations mostly carried out with the ROTSE-III and the ASAS robotic telescopes. A forward folding technique is used to determine the best-fit parameters for a model of a power law with a break in the power spectral density function (PSD). The best-fit parameters are estimated using a maximum-likelihood method with simulated light curves in conjunction with the Lomb-Scargle periodogram and the first-order structure function (SF). In addition, a new approach based upon the so-called multiple fragments variance function (MFVF) is introduced and compared to the other methods. Simulated light curves have been used to confirm the reliability of these methods as well as to estimate the uncertainties of the best-fit parameters.
- ID:
- ivo://CDS.VizieR/J/A+A/557/A12
- Title:
- Optical light curves of {gamma}-ray bursts
- Short Name:
- J/A+A/557/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive analysis of the optical and X-ray light curves (LCs) and spectral energy distributions (SEDs) of a large sample of gamma-ray burst (GRB) afterglows to investigate the relationship between the optical and X-ray emission after the prompt phase. We consider all data available in the literature, which where obtained with different instruments. We collected the optical data from the literature and determined the shapes of the optical LCs. Then, using previously presented X-ray data we modeled the optical/X-ray SEDs. We studied the SED parameter distributions and compared the optical and X-ray LC slopes and shapes.
