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1291. Classification of LAMOST DR4 galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/474/1873
Title:
Classification of LAMOST DR4 galaxies
Short Name:
J/MNRAS/474/1873
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the classification and composite spectra of galaxies in the fourth data release (DR4) of the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST). We select 40182 spectra of galaxies from LAMOST DR4, which have photometric information but no spectroscopic observations in the Sloan Digital Sky Survey (SDSS). These newly observed spectra are recalibrated and classified into six classes - passive, H{alpha}-weak, star-forming, composite, LINER and Seyfert - using the line intensity (H{beta}, [OIII] 5007, H{alpha} and [NII] 6585). We also study the correlation between spectral class and morphological type through three parameters: concentration index, (u-r) colour and D4000n index. We calculate composite spectra of high signal-to-noise ratio (S/N) for six spectral classes and, using these composites, we pick out some features that can differentiate the classes effectively, including H{beta}, Fe5015, H{gamma}A, HK and the Mg2 band. In addition, we compare our composite spectra with the SDSS ones and analyse their differences. A galaxy catalogue of 40182 newly observed spectra (36601 targets) and the composite spectra of the six classes are available online (http://sciwiki.lamost.org/downloads/wll).
1292. Classification of nova light curves
ID:
ivo://CDS.VizieR/J/AJ/140/34
Title:
Classification of nova light curves
Short Name:
J/AJ/140/34
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of 93 very-well-observed nova light curves. The light curves were constructed from 229,796 individual measured magnitudes, with the median coverage extending to 8.0mag below peak and 26% of the light curves following the eruption all the way to quiescence. Our time-binned light curves are presented in figures and as complete tabulations. We also calculate and tabulate many properties about the light curves, including peak magnitudes and dates, times to decline by 2, 3, 6, and 9mag from maximum, the time until the brightness returns to quiescence, the quiescent magnitude, power-law indices of the decline rates throughout the eruption, the break times in this decline, plus many more properties specific to each nova class. We present a classification system for nova light curves based on the shape and the time to decline by 3mag from the peak (t3). The designations are "S" for smooth light curves (38% of the novae), "P" for plateaus (21%), "D" for dust dips (18%), "C" for cusp-shaped secondary maxima (1%), "O" for quasi-sinusoidal oscillations superposed on an otherwise smooth decline (4%), "F" for flat-topped light curves (2%), and "J" for jitters or flares superposed on the decline (16%). Our classification consists of this single letter followed by the t3 value in parentheses; so, for example, V1500 Cyg is S(4), GK Per is O(13), DQ Her is D(100), and U Sco is P(3).
1293. Classification of Population II stars
ID:
ivo://CDS.VizieR/J/BaltA/5/1
Title:
Classification of Population II stars
Short Name:
J/BaltA/5/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
The astrophysical parameters compiled from literature for 809 stars of different types, mainly Population II stars, are presented. The results of classification in the Vilnius photometric system for the same stars are given. For a description of the Vilnius photometric system, see e.g. <GCPD/21>
1294. Classification of 1.5<=z<=3 HUDF galaxies
ID:
ivo://CDS.VizieR/J/ApJ/805/181
Title:
Classification of 1.5<=z<=3 HUDF galaxies
Short Name:
J/ApJ/805/181
Date:
21 Oct 2021
Publisher:
CDS
Description:
At z>~1, the distinction between merging and "normal" star-forming galaxies based on single band morphology is often hampered by the presence of large clumps which result in a disturbed, merger-like appearance even in rotationally supported disks. In this paper we discuss how a classification based on canonical, non-parametric structural indices measured on resolved stellar mass maps, rather than on single-band images, reduces the misclassification of clumpy but not merging galaxies. We calibrate the mass-based selection of mergers using the MIRAGE hydrodynamical numerical simulations of isolated and merging galaxies which span a stellar mass range of 10^9.8^-10^10.6^M_{sun}_ and merger ratios between 1:1-1:6.3. These simulations are processed to reproduce the typical depth and spatial resolution of observed Hubble Ultra Deep Field (HUDF) data. We test our approach on a sample of real z~=2 galaxies with kinematic classification into disks or mergers and on ~100 galaxies in the HUDF field with photometric/spectroscopic redshift between 1.5<=z<=3 and M>10^9.4^M_{sun}_. We find that a combination of the asymmetry A_MASS_ and M_20,MASS_ indices measured on the stellar mass maps can efficiently identify real (major) mergers with <~20% contamination from clumpy disks in the merger sample. This mass-based classification cannot be reproduced in star-forming galaxies by H-band measurements alone, which instead result in a contamination from clumpy galaxies which can be as high as 50%. Moreover, we find that the mass-based classification always results in a lower contamination from clumpy galaxies than an H-band classification, regardless of the depth of the imaging used (e.g., CANDELS versus HUDF).
1295. CL Aur BVRI light curves
ID:
ivo://CDS.VizieR/J/AJ/139/2669
Title:
CL Aur BVRI light curves
Short Name:
J/AJ/139/2669
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first extensive photometric results of CL Aur from our BVRI CCD photometry made on 22 nights from 2003 November to 2005 February. Fifteen new timings of minimum light were obtained. During the past 104yr, the orbital period has varied due to a periodic oscillation superposed on a continuous period increase. The period and semi-amplitude of the oscillation are about 21.6yr and 0.0133-day, respectively.
1296. CLEAR. II. SFRs of quiescent galaxies
ID:
ivo://CDS.VizieR/J/ApJ/898/171
Title:
CLEAR. II. SFRs of quiescent galaxies
Short Name:
J/ApJ/898/171
Date:
16 Mar 2022 00:57:30
Publisher:
CDS
Description:
The origin of the correlations between mass, morphology, quenched fraction, and formation history in galaxies is difficult to define, primarily due to the uncertainties in galaxy star formation histories (SFHs). SFHs are better constrained for higher redshift galaxies, observed closer to their formation and quenching epochs. Here we use "nonparametric" SFHs and a nested sampling method to derive constraints on the formation and quenching timescales of quiescent galaxies at 0.7<z<2.5. We model deep HST grism spectroscopy and photometry from the CLEAR (CANDELS Ly{alpha} Emission at Reionization) survey. The galaxy formation redshifts, z50 (defined as the point where they had formed 50% of their stellar mass) range from z_50_~2 (shortly prior to the observed epoch) up to z_50_~5-8. We find that early formation redshifts are correlated with high stellar-mass surface densities, log{Sigma}_1_/(M_{sun}_kpc^-2^)>10.25, where {Sigma}_1_ is the stellar mass within 1pkpc (proper kpc). Quiescent galaxies with the highest stellar-mass surface density, log{Sigma}_1_/(M_{sun}_kpc^-2^)>10.25, show a minimum formation redshift: all such objects in our sample have z_50_>2.9. Quiescent galaxies with lower surface density, log{Sigma}_1_/(M_{sun}_kpc^-2^)=9.5-10.25, show a range of formation epochs (z_50_~1.5-8), implying these galaxies experienced a range of formation and assembly histories. We argue that the surface density threshold log{Sigma}_1_/(M_{sun}_kpc^-2^)>10.25 uniquely identifies galaxies that formed in the first few Gyr after the big bang, and we discuss the implications this has for galaxy formation models.
1297. CL Eri, CM Eri, CN Eri BVIc light curves
ID:
ivo://CDS.VizieR/J/other/Obs/131.315
Title:
CL Eri, CM Eri, CN Eri BVIc light curves
Short Name:
J/other/Obs/131.
Date:
21 Oct 2021
Publisher:
CDS
Description:
A total of total of 1071 B, V, Ic-band CCD frames are taken for three GCVS RR Lyr-type variables (CL Eri, CM Eri, and CN Eri), for which only coordinates were known. Observations were made with the 76-cm telescope of the South African Astronomical Observatory using an SBIG CCD ST-10XME. The inferred periods and light-curves confirm that CL Eri (P=0.644d), which was found to exhibit the Blazhko effect, and CN Eri (P=0.580d) are RR Lyr-type variables. CM Eri is most probably a Population-Il Cepheid with a period of 0.824d.
1298. Cl* IC 348 H 254 VRI light curves
ID:
ivo://CDS.VizieR/J/MNRAS/437/906
Title:
Cl* IC 348 H 254 VRI light curves
Short Name:
J/MNRAS/437/906
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper we present new photometric and radial velocity data for the PMS {delta} Sct star H254, member of the young cluster IC 348. Photometric V, R_C_, I_C_ light curves were obtained at the Loiano and Asiago telescopes. The radial velocity data were acquired by means of the SARG@Telescopio Nazionale Galileo spectrograph. High-resolution spectroscopy allowed us to derive precise stellar parameters and the chemical composition of the star, obtaining Teff=6750+/-150K; logg=14.1+/-0.4dex and [Fe/H]=-0.07+/-0.12dex. Photometric and spectroscopic data were used to estimate the total absorption in the V band A_V_=2.06+/-0.05mag, in agreement with previous estimates. We adopted the technique of the difference in phase and amplitude between different photometric bands and radial velocities to verify that H254 is (definitely) pulsating in a radial mode. This occurrence allowed us to apply the CORS realization of the Baade-Wesselink method to obtain a value for the linear radius of H254 equal to 3.3+/-0.7R_{sun}_. This result was used in conjunction with photometry and effective temperature to derive a distance estimate of 273+/-23pc for H254, and, in turn for IC 348, the host cluster. This value is in agreement within the errors with the results derived from several past determinations and the evaluation obtained through the Hipparcos} parallaxes. Finally, we derived the luminosity of H254 and studied its position in the Hertzsprung-Russell diagram. From this analysis it results that this {delta} Scuti occupies a position close to the red edge of the instability strip, pulsates in the fundamental mode, has a mass of about 2.2M_{sun}_ and an age of 5+/-1Myr, older than previous estimates.
1299. Cl J0023+0423 and Cl J1604+4304 morphology
ID:
ivo://CDS.VizieR/J/AJ/116/584
Title:
Cl J0023+0423 and Cl J1604+4304 morphology
Short Name:
J/AJ/116/584
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a detailed morphological analysis of the galaxy populations in the first two clusters to be completed in an extensive observational study of nine high-redshift clusters of galaxies. These two clusters, Cl 0023+0423 and Cl 1604+4304, are at redshifts of z=0.84 and z=0.90, respectively. The morphological studies are based on high angular resolution imagery taken with Wide Field Planetary Camera 2 aboard the Hubble Space Telescope. These data are combined with deep, ground-based BVRI photometry and spectra taken with the Keck 10m telescopes. The morphological classifications presented in this paper consist of two parts. First, we provide a quantitative description of the structural properties of ~600 galaxies per cluster field using the Medium Deep Survey automated data reduction and object classification software. This analysis includes the galaxy position, photometry, and best-fit bulge+disk model. Second, for the brightest subsample of ~200 galaxies per cluster field, we provide a more detailed morphological description through a visual classification based on the revised Hubble classification scheme.
1300. Cl J0023+0423 and Cl J1604+4304 spectroscopy
ID:
ivo://CDS.VizieR/J/AJ/116/560
Title:
Cl J0023+0423 and Cl J1604+4304 spectroscopy
Short Name:
J/AJ/116/560
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an extensive photometric and spectroscopic study of two high-redshift clusters of galaxies based on data obtained from the Keck 10m telescopes and the Hubble Space Telescope. The clusters Cl 0023+0423 (z=0.84) and Cl 1604+4304 (z=0.90) are part of a multiwavelength program of Oke, Postman & Lubin (1998AJ....116..549O, Paper I) to study nine candidate clusters at z>~0.6. Based on these observations, we study in detail both the field and cluster populations. From the confirmed cluster members, we find that Cl 0023+0423 actually consists of two components separated by ~2900km/s. A kinematic analysis indicates that the two components are a poor cluster with ~3x10^14^M_{sun}_ and a less massive group with ~10^13^M_{sun}_. Cl 1604+4304 is a centrally concentrated, rich cluster at z=0.8967 with a velocity dispersion of 1226km/s and a mass of ~3x10^15^M_{sun}_.