- ID:
- ivo://CDS.VizieR/J/ApJS/187/275
- Title:
- Photometric histories of recurrent novae
- Short Name:
- J/ApJS/187/275
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- I collect virtually all photometry of the 10 known galactic recurrent novae (RNe) and their 37 known eruptions. This consists of my modern measures of nearly all archival plates (providing the only data for half of 37 known eruptions), my own 10000 CCD magnitudes from 1987 to present (providing virtually all of the magnitudes in quiescence for seven RNe), over 140000 visual magnitude estimates recorded by amateur astronomers (who discovered half the known eruptions), and the small scattering of magnitudes from all the literature. From this, I produce various uniform products: (1) BVRIJHK comparison star magnitudes and BV comparison star sequences to cover the entire range of eruption; (2) complete light curves for all eruptions; (3) best-fit B and V light curve templates; (4) orbital periods for all but one RN; (5) exhaustive searches for all missed eruptions; (6) measured discovery efficiencies since 1890; (7) true recurrence time scales; (8) predicted next eruption dates; (9) variations on time scales of minutes, hours, days, months, years, decades, and century; (10) uniform distances and extinctions to all RNe; (11) BV colors at peak and UBVRIJHK colors at minimum, all with extinction corrections; and (12) the spectral energy distributions over UBVRIJHK. Highlights of this work include the discoveries of one new RN, six previously unknown eruptions, and the orbital periods for half the RNe. The goal of this work is to provide uniform demographics for answering questions like the "What is the death rate of RNe in our Galaxy?" and "Are the white dwarfs gaining or losing mass over each eruption cycle?." An important use of this work is for the question of whether RNe can be the progenitors of Type Ia supernovae.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/522/A88
- Title:
- Photometric identification of BHB stars
- Short Name:
- J/A+A/522/A88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the performance of some common machine learning techniques in identifying Blue Horizontal Branch (BHB) stars from photometric data. To train the machine learning algorithms, we use previously published spectroscopic identifications of BHB stars from Sloan Digital Sky Survey (SDSS) data. We investigate the performance of three different techniques, namely k nearest neighbour classification, kernel density estimation for discriminant analysis and a support vector machine (SVM). We discuss the performance of the methods in terms of both completeness (what fraction of input BHB stars are successfully returned as BHB stars) and contamination (what fraction of contaminating sources end up in the output BHB sample). We discuss the prospect of trading off these values, achieving lower contamination at the expense of lower completeness, by adjusting probability thresholds for the classification. We also discuss the role of prior probabilities in the classification performance, and we assess via simulations the reliability of the dataset used for training. Overall it seems that no-prior gives the best completeness, but adopting a prior lowers the contamination. We find that the support vector machine generally delivers the lowest contamination for a given level of completeness, and so is our method of choice. Finally, we classify a large sample of SDSS Data Release 7 (DR7) photometry using the SVM trained on the spectroscopic sample. We identify 27,074 probable BHB stars out of a sample of 294,652 stars. We derive photometric parallaxes and demonstrate that our results are reasonable by comparing to known distances for a selection of globular clusters. We attach our classifications, including probabilities, as an electronic table, so that they can be used either directly as a BHB star catalogue, or as priors to a spectroscopic or other classification method. We also provide our final models so that they can be directly applied to new data.
- ID:
- ivo://CDS.VizieR/J/A+A/501/461
- Title:
- Photometric masses of early-type lens galaxies
- Short Name:
- J/A+A/501/461
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The largest spectroscopically selected sample of strong gravitational lens systems presented and analyzed to date is that of the Sloan Lens ACS (SLACS) survey. For the 57 massive early-type lens galaxies in the sample, photometric and spectroscopic measurements are available from the Sloan Digital Sky Survey (SDSS). By using the SDSS multicolor photometry and lens modeling, we study stellar-mass properties and the luminous and dark matter composition of the early-type lens galaxies in the sample.
- ID:
- ivo://CDS.VizieR/II/18
- Title:
- Photometric Measurements, Eggen (102,65,62) System
- Short Name:
- II/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalog of photometric measures in Eggen's (102, 65, 62) system has been compiled at the Institut d'Astronomie de l'Universite de Lausanne. A catalog of individual observations and of weighted means are included, with an explanation of the coded numbering system.
- ID:
- ivo://CDS.VizieR/II/15
- Title:
- Photometric Measurements in the UBVr 20 System
- Short Name:
- II/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the UBVr photometric system defined by Sandage and Smith (1963), (U-B)20, (B-V)20, and (V-r)20 color indices are given for stars from ten reference lists, along with a LID coded number, V magnitude, number of observations and reference. A list of weighted means is included for stars appearing on more than one list. The reference list and an explanation of the coded numbering system are included in separate files.
- ID:
- ivo://CDS.VizieR/J/ApJS/254/31
- Title:
- Photometric metallicities of stars in SkyMapper DR2
- Short Name:
- J/ApJS/254/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Milky Way's metal-poor stars are nearby ancient objects that are used to study early chemical evolution and the assembly and structure of the Milky Way. Here we present reliable metallicities of ~280000 stars with -3.75<~[Fe/H]<~-0.75 down to g=17 derived using metallicity-sensitive photometry from the second data release of the SkyMapper Southern Survey. We use the dependency of the flux through the SkyMapper v filter on the strength of the CaII K absorption features, in tandem with SkyMapper u, g, i photometry, to derive photometric metallicities for these stars. We find that metallicities derived in this way compare well to metallicities derived in large-scale spectroscopic surveys, and we use such comparisons to calibrate and quantify systematics as a function of location, reddening, and color. We find good agreement with metallicities from the APOGEE, LAMOST, and GALAH surveys, based on a standard deviation of {sigma}~0.25dex of the residuals of our photometric metallicities with respect to metallicities from those surveys. We also compare our derived photometric metallicities to metallicities presented in a number of high-resolution spectroscopic studies to validate the low-metallicity end ([Fe/H]{<}-2.5) of our photometric metallicity determinations. In such comparisons, we find the metallicities of stars with photometric [Fe/H]{<}-2.5 in our catalog show no significant offset and a scatter of {sigma}~0.31dex level relative to those in high-resolution work when considering the cooler stars (g-i>0.65) in our sample. We also present an expanded catalog containing photometric metallicities of ~720000 stars as a data table for further exploration of the metal-poor Milky Way.
- ID:
- ivo://CDS.VizieR/J/A+AS/140/29
- Title:
- Photometric monitoring of 47 late-type stars
- Short Name:
- J/A+AS/140/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present continuous multicolor photometry for 47 stars from October 1996 through June 1997. Altogether, 7073 V(RI)_c_, UBV, and by data points, each the average of three individual readings, were acquired with three automatic photoelectric telescopes (APTs) at Fairborn Observatory in southern Arizona. Most of our targets are chromospherically active single and binary stars of spectral type G to K but there are also four pre-main-sequence objects and three pulsating stars in our sample. The light variability is generally due to rotational modulation of an asymmetrically spotted stellar surface and therefore precise rotational periods and their seasonal variations are determined from Fourier analysis. We also report on photometric variations of {gamma} CrB (A0V) with a period of 0.44534 days. All data are available in numerical form.
- ID:
- ivo://CDS.VizieR/J/AJ/158/180
- Title:
- Photometric observations of AE Cassiopeia
- Short Name:
- J/AJ/158/180
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- AE Cas was observed some 40 yr ago by Srivastava & Kandpal (1984AcA....34..281S) and was analyzed by Kopal's Fourier frequency-domain technique. No further precision observations have taken place until the present study, which represents the first modern synthetic analysis of light curves using the 2016 version of the Wilson-Devinney (W-D) Program. It was observed in 2015 October 2, 3 and 23, inclusive, at Dark Sky Observatory in North Carolina with the 0.81 m reflector of Appalachian State University and the 0.9 m reflector at Kitt Peak National Observatory remotely through the Southeastern Association for Research in Astronomy (SARA) consortia. V, R_c_, I_c_ observations were taken. Five times of minimum light were determined from our present observations, which include three primary eclipses and two secondary eclipses. In addition, eight observations at minima were introduced as low weighted times of minimum light from archived All-Sky Automated Survey for Supernovae Variable Star Catalog (ASAS) data and 74 times of minimum light from the literature, some of which were from visual observations. This period study covers an interval of some 89 yr. The period was found to be decaying at a constant rate with a high level of confidence. A VR_c_I_c_ simultaneous W-D Program solution indicates that the system has a mass ratio somewhat less than unity (q=0.856+/-0.001), and a component temperature difference of ~2060 K. A q-search was performed and the mass ratio minimized at the above value. The large temperature difference in the components verifies that the binary is not yet in contact. No spots were needed for the solution. The fill-out of our model is 83.2% for the primary component (smaller radius) and 99.1% for the secondary component. So, it is near a classical Algol configuration.
- ID:
- ivo://CDS.VizieR/J/ApJ/626/L5
- Title:
- Photometric observations of GRB 041006
- Short Name:
- J/ApJ/626/L5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep optical photometry of the afterglow of gamma-ray burst (GRB) 041006 and its associated hypernova obtained over 65 days after detection (55 R-band epochs on 10 different nights). Our early data (t<4days) joined with published GCN data indicate a steepening decay, approaching F_{nu}_{prop. to}t^-0.6^ at early times (t<<1day) and F_{nu}_{prop.to}t^-1.3^ at late times.
- ID:
- ivo://CDS.VizieR/J/A+AS/113/473
- Title:
- Photometric observations of PMS objects
- Short Name:
- J/A+AS/113/473
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the observational data of a photometric monitoring of 24 pre-main sequence objects: T Tauri stars, Ae/Be Herbig stars and some unclassified objects. Observations were carried out from July 1988 to August 1992, using the UBV(RI)_c system. Variability with time scales from days to years and amplitudes in the V band larger than 0.1 mag is found for a part of this sample. The analysis of the possible causes of this variability are discussed in separate papers (Fernandez & Eiroa 1995a,b).
