- ID:
- ivo://CDS.VizieR/J/A+A/508/593
- Title:
- GRB 080710 bright optical/NIR afterglow
- Short Name:
- J/A+A/508/593
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the optical/near-infrared light curve of the afterglow of GRB 080710 in the context of rising afterglows. Optical and near-infrared photometry was performed using the seven-channel imager GROND and the Tautenburg Schmidt telescope. X-ray data were provided by the X-ray Telescope onboard the Swift satellite. We construct an empirical light curve model using the available broadband data, which is well-sampled in the time and frequency domains.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/141/36
- Title:
- GRB 080607 multi-band light curves
- Short Name:
- J/AJ/141/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present early-time optical through infrared photometry of the bright Swift gamma-ray burst (GRB) 080607, starting only 6s following the initial trigger in the rest frame. Complemented by our previously published spectroscopy, this high-quality photometric data set allows us to solve for the extinction properties of the redshift 3.036 sightline, giving perhaps the most detailed information to date on the ultraviolet continuum absorption properties of any sightline outside our Local Group.
- ID:
- ivo://CDS.VizieR/J/ApJ/770/95
- Title:
- g'RcIcJ photometry of the hot Uranus GJ3470b
- Short Name:
- J/ApJ/770/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical (g', R_c_, and I_c_) to near-infrared (J) simultaneous photometric observations for a primary transit of GJ3470b, a Uranus-mass transiting planet around a nearby M dwarf, by using the 50cm MITSuME telescope and the 188cm telescope, both at the Okayama Astrophysical Observatory. From these data, we derive the planetary mass, radius, and density as 14.1 +/-1.3M_{Earth}_, 4.32_-0.10_^+0.21^R_{Earth}_, and 0.94+/-0.12g/cm3, respectively, thus confirming the low density that was reported by Demory et al. (2013ApJ...768..154D) based on the Spitzer/IRAC 4.5{mu}m photometry (0.72_-0.12_^+0.13^g/cm3). Although the planetary radius is about 10% smaller than that reported by Demory et al., this difference does not alter their conclusion that the planet possesses a hydrogen-rich envelope whose mass is approximately 10% of the planetary total mass. On the other hand, we find that the planet-to-star radius ratio (R_p_/R_s_) in the J band (0.07577_-0.00075_^+0.00072^) is smaller than that in the I_c_(0.0802+/-0.0013) and 4.5{mu}m (0.07806_-0.00054_^+0.00052^) bands by 5.8%+/-2.0% and 2.9%+/-1.1%, respectively. A plausible explanation for the differences is that the planetary atmospheric opacity varies with wavelength due to absorption and/or scattering by atmospheric molecules. Although the significance of the observed R_p_/R_s_variations is low, if confirmed, this fact would suggest that GJ3470b does not have a thick cloud layer in the atmosphere. This property would offer a wealth of opportunity for future transmission-spectroscopic observations of this planet to search for certain molecular features, such as H_2_O, CH_4_, and CO, without being prevented by clouds.
- ID:
- ivo://CDS.VizieR/J/AJ/160/277
- Title:
- gri-light curve of near-Earth asteroid 2020 CD3
- Short Name:
- J/AJ/160/277
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- We report on our detailed characterization of Earth's second known temporary natural satellite, or minimoon, asteroid 2020CD3. An artificial origin can be ruled out based on its area-to-mass ratio and broadband photometry, which suggest that it is a silicate asteroid belonging to the S or V complex in asteroid taxonomy. The discovery of 2020CD3 allows for the first time a comparison between known minimoons and theoretical models of their expected physical and dynamical properties. The estimated diameter of 1.2_-0.2_^+0.4^m and geocentric capture approximately a decade after the first known minimoon, 2006RH120, are in agreement with theoretical predictions. The capture duration of 2020CD3 of at least 2.7yr is unexpectedly long compared to the simulation average, but it is in agreement with simulated minimoons that have close lunar encounters, providing additional support for the orbital models. 2020CD3's atypical rotation period, significantly longer than theoretical predictions, suggests that our understanding of meter-scale asteroids needs revision. More discoveries and a detailed characterization of the population can be expected with the forthcoming Vera C. Rubin Observatory Legacy Survey of Space and Time.
- ID:
- ivo://CDS.VizieR/J/ApJ/756/73
- Title:
- gri light curves of the low-luminosity AGN NGC 4395
- Short Name:
- J/ApJ/756/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of broadband photometric reverberation mapping (RM) to measure the radius of the broad-line region, and subsequently the black hole mass (M_BH_), in the nearby, low-luminosity active galactic nuclei NGC 4395. Using the Wise Observatory's 1m telescope equipped with the Sloan Digital Sky Survey g', r', and i' broadband filters, we monitored NGC 4395 for nine consecutive nights and obtained three light curves each with over 250 data points. The g' and r' bands include time variable contributions from H{beta} and H{alpha}, respectively, plus continuum. The i' band is free of broad lines and covers exclusively continuum. We show that by looking for a peak in the difference between the cross-correlation and the auto-correlation functions for all combinations of filters, we can get a reliable estimate of the time lag necessary to compute M_BH_. We measure the time lag for H{alpha} to be 3.6+/-0.8hr, comparable to previous studies using the line-resolved spectroscopic RM method. We argue that this lag implies a black hole mass of M_BH_=(4.9+/-2.6)x10^4^M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/ApJS/247/49
- Title:
- gri obs. of the blazar S5 0716+714 (2017-2019)
- Short Name:
- J/ApJS/247/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We continuously monitored the blazar S5 0716+714 in the optical g, r, and i bands from 2017 November 10 to 2019 June 6. The total number of observations is 201 nights including 26973 data points. This is a very large quasi-simultaneous multicolor sample for the blazar. The average time spans and time resolutions are 3.4hr and 2.9min per night, respectively. During the period of observations, the target source in the r band brightens from 14.16m to 12.29m together with five prominent subflares, and then becomes fainter to 14.76m, and again brightens to 12.94m with seven prominent subflares. For the long-term variations, we find a strong flatter-when-brighter (FWB) trend at a low-flux state and then a weak FWB trend at a higher-flux state. A weak FWB trend at a low-flux state and then a strong FWB trend at a higher-flux state are also reported. Most subflares show strong FWB trends, except for two flares with a weak FWB trend. The particle acceleration and cooling mechanisms together with the superposition of the different FWB slopes from the subflares likely explain the optical color behaviors. A scenario of bent jet is discussed.
- ID:
- ivo://CDS.VizieR/J/ApJ/675/1233
- Title:
- gri photometry in M37 (NGC 2099)
- Short Name:
- J/ApJ/675/1233
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a deep (15~<r~<23 ), 20 night survey for transiting planets in the intermediate-age open cluster M37 (NGC 2099) using the Megacam wide-field mosaic CCD camera on the 6.5m MMT. In this paper we describe the observations and data reduction procedures for the survey and analyze the stellar content and dynamical state of the cluster. By combining high-resolution spectroscopy with existing BVI_C_K_s and new gri color-magnitude diagrams, we determine the fundamental cluster parameters: t=485+/-28Myr, without overshooting (t=550+/-30Myr, with overshooting), E(B-V)=0.227+/-0.038, (m-M)_V_=11.57+/-0.13, and [M/H]=+0.045+/-0.044, which are in good agreement with, although more precise than, previous measurements. We determine the mass function down to 0.3M_{sun}_ and use this to estimate the total cluster mass of 3640+/-170M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/ApJ/857/132
- Title:
- gri photometry of NGC 796 cluster
- Short Name:
- J/ApJ/857/132
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 796 is a massive young cluster located 59kpc from us in the diffuse intergalactic medium of the 1/5-1/10Z_{sun}_ Magellanic Bridge, allowing us to probe variations in star formation and stellar evolution processes as a function of metallicity in a resolved fashion, and providing a link between resolved studies of nearby solar-metallicity and unresolved distant metal-poor clusters located in high-redshift galaxies. In this paper, we present adaptive optics griH{alpha} imaging of NGC 796 (at 0.5", which is ~0.14pc at the cluster distance) along with optical spectroscopy of two bright members to quantify the cluster properties. Our aim is to explore whether star formation and stellar evolution vary as a function of metallicity by comparing the properties of NGC 796 to higher-metallicity clusters. We find an age of 20_-5_^+12^Myr from isochronal fitting of the cluster main sequence in the color-magnitude diagram. Based on the cluster luminosity function, we derive a top-heavy stellar initial mass function (IMF) with a slope {alpha}=1.99+/-0.2, hinting at a metallicity and/or environmental dependence of the IMF, which may lead to a top-heavy IMF in the early universe. Study of the H{alpha} emission-line stars reveals that classical Be stars constitute a higher fraction of the total B-type stars when compared with similar clusters at greater metallicity, providing some support to the chemically homogeneous theory of stellar evolution. Overall, NGC 796 has a total estimated mass of 990+/-200M_{sun}_, and a core radius of 1.4+/-0.3pc, which classifies it as a massive young open cluster, unique in the diffuse interstellar medium of the Magellanic Bridge.
- ID:
- ivo://CDS.VizieR/J/AJ/149/183
- Title:
- gri photometry of variables in NGC 4258
- Short Name:
- J/AJ/149/183
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a ground-based survey for Cepheid variables in NGC4258. This galaxy plays a key role in the Extragalactic Distance Scale due to its very precise and accurate distance determination via very long baseline interferometry observations of water masers. We imaged two fields within this galaxy using the Gemini North telescope and the Gemini Multi-Object Spectrograph, obtaining 16 epochs of data in the Sloan Digital Sky Survey gri bands over 4yr. We carried out point-spread function photometry and detected 94 Cepheids with periods between 7 and 127 days, as well as an additional 215 variables which may be Cepheids or Population II pulsators. We used the Cepheid sample to test the absolute calibration of theoretical gri Period-Luminosity relations and found good agreement with the maser distance to this galaxy. The expected data products from the Large Synoptic Survey Telescope should enable Cepheid searches out to at least 10Mpc.
- ID:
- ivo://CDS.VizieR/J/A+A/531/A39
- Title:
- g'r'i'z'JHKs light curves of GRB 081029
- Short Name:
- J/A+A/531/A39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- GROND multi-colour follow-up of GRB 081029 is used to study the nature of the late-time extremely fast rebrightening that appears in the optical-NIR light-curve of the afterglow of GRB 081029.
