Search

Start Over Subject optical astronomy Capability Type Simple Cone Search
1421. Local Group dE galaxies. II.
ID:
ivo://CDS.VizieR/J/ApJ/711/361
Title:
Local Group dE galaxies. II.
Short Name:
J/ApJ/711/361
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present kinematic and metallicity profiles for the M 31 dwarf elliptical (dE) satellite galaxies NGC 147 and NGC 185. The profiles represent the most extensive spectroscopic radial coverage for any dE galaxy, extending to a projected distance of 8 half-light radii (8r_eff_~14'). We achieve this coverage via Keck/DEIMOS multislit spectroscopic observations of 520 and 442 member red giant branch stars in NGC 147 and NGC 185, respectively. In contrast to previous studies, we find that both dEs have significant internal rotation. We measure a maximum rotational velocity of 17+/-2km/s for NGC 147 and 15+/-5km/s for NGC 185. The velocity dispersions decrease gently with radius with average dispersions of 16+/-1km/s and 24+/-1km/s for NGC 147 and NGC 185, respectively. The average metallicities for NGC 147 and NGC 185 are [Fe/H]=-1.1+/-0.1 and [Fe/H]=-1.3+/-0.1, respectively; both dEs have internal metallicity dispersions of 0.5dex, but show no evidence for a radial metallicity gradient.
1422. Local structure & star formation history of the MW
ID:
ivo://CDS.VizieR/J/AJ/158/122
Title:
Local structure & star formation history of the MW
Short Name:
J/AJ/158/122
Date:
09 Mar 2022 22:00:00
Publisher:
CDS
Description:
Gaia DR2 (Cat. I/345) provides unprecedented precision in measurements of the distance and kinematics of stars in the solar neighborhood. Through applying unsupervised machine learning on DR2's 5D data set (3D position + 2D velocity), we identify a number of clusters, associations, and comoving groups within 1 kpc and |b|<30{deg} (many of which have not been previously known). We estimate their ages with the precision of ~0.15 dex. Many of these groups appear to be filamentary or string-like, oriented in parallel to the Galactic plane, and some span hundreds of parsec in length. Most of these string lack a central cluster, indicating that their filamentary structure is primordial, rather than the result of tidal stripping or dynamical processing. The youngest strings (<100 Myr) are orthogonal to the Local Arm. The older ones appear to be remnants of several other arm-like structures that cannot be presently traced by dust and gas. The velocity dispersion measured from the ensemble of groups and strings increase with age, suggesting a timescale for dynamical heating of ~300 Myr. This timescale is also consistent with the age at which the population of strings begins to decline, while the population in more compact groups continues to increase, suggesting that dynamical processes are disrupting the weakly bound string populations, leaving only individual clusters to be identified at the oldest ages. These data shed a new light on the local galactic structure and a large-scale cloud collapse.
1423. Long-term BVRI photometry of 15 PMS stars
ID:
ivo://CDS.VizieR/J/other/RAA/18.137
Title:
Long-term BVRI photometry of 15 PMS stars
Short Name:
J/other/RAA/18.1
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper reports results from the multicolor photometric observations of 15 pre-main sequence stars collected in the period September 2010 - October 2017. The stars from our study are located in the star-forming HII region IC 5070. These objects were previously detected as either emission line stars, flare stars, T Tauri variables or Herbig Ae/Be stars. Photometric observations, especially concerning the long-term behavior of the objects, are missing in the literature. We present the first photometric monitoring for all stars from our study. The analysis of the obtained BVRI photometric data allows us to draw the conclusion that all investigated objects are variable stars. In the case of LkHa 146, we identified previously unknown periodicity in its photometric variability.
1424. Long-term monitoring of {gamma} Dor stars
ID:
ivo://CDS.VizieR/J/A+A/499/967
Title:
Long-term monitoring of {gamma} Dor stars
Short Name:
J/A+A/499/967
Date:
21 Oct 2021
Publisher:
CDS
Description:
gamma Dor stars are excellent targets for asteroseismology since the gravity modes present in these stars probe the deep stellar interiors. Mode identification will improve the knowledge of these stars considerably. A selected group of gamma Dor stars and some candidates were observed with the Mercator telescope to find and/or confirm the periodicities in the light variations and to derive reliable amplitude ratios in different pass bands. A frequency analysis was performed on all new data obtained in the Geneva photometric system. In order to have more reliable and accurate frequencies, the new data were combined with similar data from the literature and with Hipparcos observations. A set of frequencies that minimized the residuals in a harmonic fit was searched for while allowing means and amplitudes to vary from one observation set to another.
1425. Long-Term Multicolour Photometry of YSOs
ID:
ivo://CDS.VizieR/J/other/PASA/32.21
Title:
Long-Term Multicolour Photometry of YSOs
Short Name:
J/other/PASA/32.
Date:
21 Oct 2021
Publisher:
CDS
Description:
Results from long-term multicolour optical photometric observations of the pre-main sequence stars FHO 26, FHO 27, FHO 28, FHO 29, and V1929 Cyg collected during the period from 1997 June to 2014 December are presented. The objects are located in the dense molecular cloud L935, named 'Gulf of Mexico', in the field between the North America and Pelican nebulae. All stars from our study exhibit strong photometric variability in all optical passbands. Using our BVRI observations and data published by other authors, we tried to define the reasons for the observed brightness variations. The presented paper is a part of our long-term photometric study of the young stellar objects in the region of 'Gulf of Mexico'.
1426. Long-term photometry for 4 O-rich PPne
ID:
ivo://CDS.VizieR/J/AJ/149/184
Title:
Long-term photometry for 4 O-rich PPne
Short Name:
J/AJ/149/184
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new light curves covering 14-19years of observations of four bright proto-planetary nebulae (PPNs), all oxygen-rich and of F spectral type. They each display cyclical light curves with significant variations in amplitude. All four were previously known to vary in light. Our data were combined with published data and searched for periodicity. The results are as follows: IRAS 19475+3119 (HD331319; 41.0days), 17436+5003 (HD161796; 45.2days), 19386+0155 (101.8days), and 18095+2704 (113.3days). The two longer periods are in agreement with previous studies while the two shorter periods each reveal for the first time a dominant period over these long observing intervals. Multiple periods were also found for each object. The secondary periods were all close to the dominant periods, with P_2_/P_1_ ranging from 0.86 to 1.06. The variations in color reveal maximum variations in T_eff_of 400-770K. These variations are due to pulsations in these post-asymptotic giant branch objects. Maximum seasonal light variations are all less than 0.23mag (V), consistent for their temperatures and periods with the results of Hrivnak et al. for 12 C-rich PPNs. For all of these PPNs, there is an inverse relationship between period and temperature; however, there is a suggestion that the period-temperature relationship may be somewhat steeper for the O-rich than for the C-rich PPNs.
1427. Long-term photometry of pre-MS stars
ID:
ivo://CDS.VizieR/J/A+A/568/A49
Title:
Long-term photometry of pre-MS stars
Short Name:
J/A+A/568/A49
Date:
21 Oct 2021
Publisher:
CDS
Description:
To broaden the search and study stars in the early evolutionary phase, we investigated a sample of 17 pre-main sequence objects previously detected as either H{alpha} emission-line pre-main sequence stars or T Tauri variables located in the field of the North America/Pelican Nebula complex. Johnson-Cousins B, V, Rc, Ic magnitudes and mean color indices for the program stars are determined from more than 12400 measurements from archive photographic plates and from CCD data collected at 7 observatories covering the period of almost 60 years from 1954 up to 2013. We complemented previously rare insights on the photometry of the program stars and presented their photometric history, which for almost all program stars is the first long term photometric monitoring on a timescale of 6 decades. Eight program stars are found to be classical T Tauri stars of variability type II, while 6 program stars are weak-line T Tauri stars of variability type I. For the first time, periodicity is found for three stars: V1716 Cyg indicates a 4.15 day period, V2051 Cyg indicates a 384 day period, and V521 Cyg a period of 503 days.
1428. Long-term photometry of Variables I.
ID:
ivo://CDS.VizieR/II/170
Title:
Long-term photometry of Variables I.
Short Name:
II/170
Date:
21 Oct 2021
Publisher:
CDS
Description:
This is the first catalogue of photometric data in the Stroemgren system obtained during the period October 1982 - September 1986. Full description can be found in ESO report SP 8. Since our goal is not absolute (all-sky) photometry, the observations should be used for differential photometry only. The mean values of the r.m.s. deviations of the differential measurements of comparison stars are around (from Table 5 of paper) ------------------------------------ System y b-y m1 c1 ------------------------------------ 1 0.0109 0.0088 0.0133 0.0136 4 0.0068 0.0057 0.0079 0.0118 5 0.0087 0.0070 0.0114 0.0114 6 0.0090 0.0078 0.0126 0.0132 7 0.0071 0.0033 0.0041 0.0065 ------------------------------------
1429. Long-term photometry of Variables II
ID:
ivo://CDS.VizieR/II/188
Title:
Long-term photometry of Variables II
Short Name:
II/188
Date:
21 Oct 2021
Publisher:
CDS
Description:
The second catalogue of the LTPV programme contains photometric data obtained during the period October 1986 - September 1990. Full description can be found in ESO reports SP 8 and 12. The data presented here have been upgraded since the printing of catalogue ESO SR 12; a major change is the use of a quite different standard, namely the ESO SAT (Stroemgren Automatic Telescope) instrumental system has been used as standard. The instrumental systems 6 and 8 can be obtained by applying the following color matrices (see ESO SR 12, page 4, Eq. (3)), inverted (b-y , y , m1 , c1): SYSTEM 6 1.0518 0.0000 0.0000 0.0000 0.0094 1.0000 0.0000 0.0000 -0.1238 0.0000 1.1206 0.0000 0.0426 0.0000 0.0000 1.0352 SYSTEM 8 1.0476 0.0000 0.0000 0.0000 0.0384 1.0000 0.0000 0.0000 -0.0877 0.0000 1.0487 0.0000 -0.2657 0.0000 0.0000 0.9732 It also very easy to go back to the same standard as in ESO SR 8 by applying the transformations given in Table 3 of ESO SR 12 (page 3). Note that the faint star C7060 is not identified so far. The mean values of the r.m.s. deviations of the differential measurements of comparison stars are around (from Table 5 of paper) ------------------------------------ System y b-y m1 c1 ------------------------------------ 6 0.0069 0.0058 0.0122 0.0129 7 0.0064 0.0030 0.0039 0.0067 8 0.0068 0.0061 0.0110 0.0097 ------------------------------------
1430. Long-term photometry of Variables III
ID:
ivo://CDS.VizieR/II/200
Title:
Long-term photometry of Variables III
Short Name:
II/200
Date:
21 Oct 2021
Publisher:
CDS
Description:
This is the third catalogue of photometric data in the Stroemgren system obtained during the period October 1990-January 1992 in the framework of the Long-Term Photometry of Variables (LTPV) program at the European Southern Observatory. All data have been obtained with the Danish 50-cm telescope. The mean values of the r.m.s. deviations of the differential measurements of comparison stars are around (from Table 4 of paper) ------------------------------ y b-y m1 c1 ------------------------------ 0.005 0.002 0.004 0.006 ------------------------------