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2851. I-band light curves of OGLE LMC Miras
ID:
ivo://CDS.VizieR/J/AJ/152/164
Title:
I-band light curves of OGLE LMC Miras
Short Name:
J/AJ/152/164
Date:
21 Oct 2021
Publisher:
CDS
Description:
We develop a nonlinear semi-parametric Gaussian process model to estimate periods of Miras with sparsely sampled light curves. The model uses a sinusoidal basis for the periodic variation and a Gaussian process for the stochastic changes. We use maximum likelihood to estimate the period and the parameters of the Gaussian process, while integrating out the effects of other nuisance parameters in the model with respect to a suitable prior distribution obtained from earlier studies. Since the likelihood is highly multimodal for period, we implement a hybrid method that applies the quasi-Newton algorithm for Gaussian process parameters and search the period/frequency parameter space over a dense grid. A large-scale, high-fidelity simulation is conducted to mimic the sampling quality of Mira light curves obtained by the M33 Synoptic Stellar Survey. The simulated data set is publicly available and can serve as a testbed for future evaluation of different period estimation methods. The semi-parametric model outperforms an existing algorithm on this simulated test data set as measured by period recovery rate and quality of the resulting period-luminosity relations.
2852. I-band light curves of SNe II from OGLE-IV
ID:
ivo://CDS.VizieR/J/MNRAS/449/1753
Title:
I-band light curves of SNe II from OGLE-IV
Short Name:
J/MNRAS/449/1753
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study a sample of 11 Type II supernovae (SNe) discovered by the OGLE-IV survey. All objects have well-sampled I-band light curves, and at least one spectrum. We find that two or three of the 11 SNe have a declining light curve, and spectra consistent with other SNe II-L, while the rest have plateaus that can be as short as 70 d, unlike the 100 d typically found in nearby galaxies. The OGLE SNe are also brighter, and show that magnitude-limited surveys find SNe that are different than usually found in nearby galaxies. We discuss this sample in the context of understanding Type II SNe as a class and their suggested use as standard candles.
2853. I-band photometry of cosmic flows
ID:
ivo://CDS.VizieR/J/MNRAS/415/1935
Title:
I-band photometry of cosmic flows
Short Name:
J/MNRAS/415/1935
Date:
21 Oct 2021
Publisher:
CDS
Description:
Within the "Cosmic Flows" project, I-band photometry of 524 relatively nearby galaxies has been carried out over the course of several years with the University of Hawaii 2.2-m telescope and a camera with a 7.5-arcmin field of view. The primary scientific goal was to provide global magnitudes and inclinations for galaxies for the purpose of measuring distances through the correlation between galaxy luminosities and rotation rates. The 1{sigma} accuracy on a total magnitude is 0.08mag. The observations typically extend to 7-8 exponential disc scalelengths, so the data are useful for studies of the structural properties of galaxies.
2854. i-band photometry of HAT-P-16
ID:
ivo://CDS.VizieR/J/ApJ/720/1118
Title:
i-band photometry of HAT-P-16
Short Name:
J/ApJ/720/1118
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of HAT-P-16b, a transiting extrasolar planet orbiting the V=10.8mag F8 dwarf GSC 2792-01700, with a period P=2.775960+/-0.000003 days, transit epoch T_c_=2455027.59293+/-0.00031 (BJD10), and transit duration 0.1276+/-0.0013 days. The host star has a mass of 1.22+/-0.04M_{sun}_, radius of 1.24+/-0.05R_{sun}_, effective temperature 6158+/-80K, and metallicity [Fe/H]=+0.17+/-0.08. The planetary companion has a mass of 4.193+/-0.094M_J_ and radius of 1.289+/-0.066R_J_, yielding a mean density of 2.42+/-0.35g/cm^3^. Comparing these observed characteristics with recent theoretical models, we find that HAT-P-16b is consistent with a 1Gyr H/He-dominated gas giant planet. HAT-P-16b resides in a sparsely populated region of the mass-radius diagram and has a non-zero eccentricity of e=0.036 with a significance of 10{sigma}.
2855. i-band variability of YSOs
ID:
ivo://CDS.VizieR/II/362
Title:
i-band variability of YSOs
Short Name:
II/362
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an i-band photometric study of over 800 young stellar objects in the OB association Cep OB3b, which samples timescales from 1 minute to ten years. Using structure functions we show that on all timescales (tau) there is a monotonic decrease in variability from Class I to Class II through the transition disc (TD) systems to Class III, i.e. the more evolved systems are less variable. The Class Is show an approximately power-law increase (tau^0.8^) in variability from timescales of a few minutes to ten years. The Class II, TDs and Class III systems show a qualitatively different behaviour with most showing a power-law increase in variability to a timescale corresponding to the rotational period of the star, with little additional variability beyond that timescale. However, about a third of the Class IIs show lower overall variability, but their variability is still increasing at 10 years. This behaviour can be explained if all Class IIs have two primary components to their variability. The first is an underlying roughly power-law variability spectrum, which evidence from the infrared suggests is driven by accretion rate changes. The second component is an approximately sinusoidal and results from the rotation of the star. We suggest that the systems with dominant longer-timescale variability have a smaller rotational modulation either because they are seen at low inclinations or have more complex magnetic field geometries. We derive a new way of calculating structure functions for large simulated datasets (the "fast structure function"), based on fast Fourier transforms.
2856. IC 4665
ID:
ivo://CDS.VizieR/J/AJ/105/1441
Title:
IC 4665
Short Name:
J/AJ/105/1441
Date:
21 Oct 2021
Publisher:
CDS
Description:
The results of a combined astrometric, photometric, and spectroscopic program to identify members of the open cluster IC 4665 are presented. Numerous new proper motion/photometric candidate members and at least 23 M dwarfs with H-alpha emission have been identified. A reanalysis of IC 4665's age using different methods yields conflicting results ranging from approx. 3x10^7^ yr to the age of the Pleiades. This study provides a list of candidate cluster members in the intermediate and low-mass regime of this cluster. Future spectroscopic observations of these candidates should eventually identify true cluster members. The results of new echelle observations of some candidates and the photometric monitoring of one apparent cluster member are given in an appendix.
2857. IC 4996 CCD photometry
ID:
ivo://CDS.VizieR/J/AJ/116/1801
Title:
IC 4996 CCD photometry
Short Name:
J/AJ/116/1801
Date:
21 Oct 2021
Publisher:
CDS
Description:
The results of a UBV CCD photometric study of the cluster IC 4996 are presented. We obtain new values for the cluster parameters: E(B-V)=0.71+/-0.08, V_0_-M_V_=11.9+/-0.1, and age=(7.5+/-3)x10^6^yr. The combined evidence from the photometric diagrams suggests the presence of a number of premain-sequence (PMS) cluster members with spectral types ~A0 to F5. The interpretation of these objects as PMS candidates is further supported by independent results from CCD uvbyH{beta} observations. If confirmed, these stars would bridge the existing gap in the sample of PMS stars, between the coolest Herbig AeBe stars (HAeBe), and the hottest T Tauri stars. These PMS candidates are located some 0.5 and 1 mag above the main sequence in the V-(B-V) diagram, around the location of spectral types AF. This feature, together with their locations in the (U-B)-(B-V) diagram and the interpretation that they are PMS members, suggest an additional reddening law with a slope {alpha}=E(U-B)/E(B-V)~0.55, probably caused by circumstellar material.
2858. IC 4665 DANCe
ID:
ivo://CDS.VizieR/J/A+A/631/A57
Title:
IC 4665 DANCe
Short Name:
J/A+A/631/A57
Date:
21 Oct 2021
Publisher:
CDS
Description:
The study of star formation is extremely challenging due to the lack of complete and clean samples of young, nearby clusters, and star forming regions. The recent Gaia DR2 catalogue complemented with the deep, ground based COSMIC DANCe catalogue offers a new database of unprecedented accuracy to revisit the membership of clusters and star forming regions. The 30 Myr open cluster IC 4665 is one of the few well-known clusters of this age and it is an excellent target where to test evolutionary models and study planetary formation. We aim to provide a comprehensive membership analysis of IC 4665 and to study the following properties: empirical isochrones, distance, magnitude distribution, present-day system mass function, and spatial distribution. We use the Gaia DR2 catalogue together with the DANCe catalogue to look for members using a probabilistic model of the distribution of the observable quantities in both the cluster and background populations. We obtain a final list of 819 candidate members which cover a 12.4 magnitude range (7<J<19.4). We find that 50% are new candidates, and we estimate a conservative contamination rate of 20%. This unique sample of members allows us to obtain a present-day system mass function in the range of 0.02-6M_{sun}_, which reveals a number of details not seen in previous studies. In addition, they favour a spherically symmetric spatial distribution for this young open cluster. Our membership analysis represents a significant increase in the quantity and quality (low-contamination) with respect to previous studies. As such, it offers an excellent opportunity to revisit other fundamental parameters such as the age.
2859. IC 348 membership
ID:
ivo://CDS.VizieR/J/ApJ/593/1093
Title:
IC 348 membership
Short Name:
J/ApJ/593/1093
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a new census of the stellar and substellar members of the young cluster IC 348. We have obtained images at I and Z for a 42'x28' field encompassing the cluster and have combined these measurements with previous optical and near-infrared photometry. From spectroscopy of candidate cluster members appearing in these data, we have identified 122 new members, 15 of which have spectral types of M6.5M9, corresponding to masses of ~0.08-0.015M_{sun}_ by recent evolutionary models. The latest census for IC 348 now contains a total of 288 members, 23 of which are later than M6 and thus are likely to be brown dwarfs.
2860. ICMF of super star clusters
ID:
ivo://CDS.VizieR/J/AJ/135/823
Title:
ICMF of super star clusters
Short Name:
J/AJ/135/823
Date:
21 Oct 2021
Publisher:
CDS
Description:
The initial cluster mass function (ICMF) is a fundamental property of star formation in galaxies. To gauge its universality, we measure and compare the ICMFs in irregular and spiral galaxies. Our sample of irregular galaxies is based on 13 nearby galaxies selected from a volume-limited sample from the fifth data release of the Sloan Digital Sky Survey (SDSS), from which about 320 young (<=20Myr), massive (>~3x10^49M_{sun}_) clusters or associations were selected using an automated source extraction routine. The extinctions, ages, and masses were determined by comparing their u'g'i'z' magnitudes to those generated from starburst models.