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8441. ZTF observations of FRB 180916.J0158+65
ID:
ivo://CDS.VizieR/J/ApJ/896/L2
Title:
ZTF observations of FRB 180916.J0158+65
Short Name:
J/ApJ/896/L2
Date:
07 Dec 2021
Publisher:
CDS
Description:
The discovery rate of fast radio bursts (FRBs) is increasing dramatically thanks to new radio facilities. Meanwhile, wide-field instruments such as the 47deg^2^ Zwicky Transient Facility (ZTF) survey the optical sky to study transient and variable sources. We present serendipitous ZTF observations of the Canadian Hydrogen Intensity Mapping Experiment (CHIME) repeating source FRB180916.J0158+65 that was localized to a spiral galaxy 149Mpc away and is the first FRB suggesting periodic modulation in its activity. While 147 ZTF exposures corresponded to expected high-activity periods of this FRB, no single ZTF exposure was at the same time as a CHIME detection. No >3{sigma} optical source was found at the FRB location in 683 ZTF exposures, totaling 5.69hr of integration time. We combined ZTF upper limits and expected repetitions from FRB 180916.J0158+65 in a statistical framework using a Weibull distribution, agnostic of periodic modulation priors. The analysis yielded a constraint on the ratio between the optical and radio fluences of {eta}<~200, corresponding to an optical energy E_opt_<~3x10^46^erg for a fiducial 10Jy.ms FRB (90% confidence). A deeper (but less statistically robust) constraint of {eta}<~3 can be placed assuming a rate of r(>5Jy.ms)=1hr^-1^ and 1.2+/-1.1 FRB occurring during exposures taken in high-activity windows. The constraint can be improved with shorter per-image exposures and longer integration time, or observing FRBs at higher Galactic latitudes. This work demonstrated how current surveys can statistically constrain multiwavelength counterparts to FRBs even without deliberately scheduled simultaneous radio observation.
8442. Zwicky Transient Facility BTS. I.
ID:
ivo://CDS.VizieR/J/ApJ/895/32
Title:
Zwicky Transient Facility BTS. I.
Short Name:
J/ApJ/895/32
Date:
16 Mar 2022 00:25:08
Publisher:
CDS
Description:
The Zwicky Transient Facility (ZTF) is performing a three-day cadence survey of the visible northern sky (~3{pi}) with newly found transient candidates announced via public alerts. The ZTF Bright Transient Survey (BTS) is a large spectroscopic campaign to complement the photometric survey. BTS endeavors to spectroscopically classify all extragalactic transients with m_peak_<~18.5mag in either the g_ZTF_ or r_ZTF_ filters, and publicly announce said classifications. BTS discoveries are predominantly supernovae (SNe), making this the largest flux-limited SN survey to date. Here we present a catalog of 761 SNe, classified during the first nine months of ZTF (2018 April 1-2018 December 31). We report BTS SN redshifts from SN template matching and spectroscopic host-galaxy redshifts when available. We analyze the redshift completeness of local galaxy catalogs, the redshift completeness fraction (RCF; the ratio of SN host galaxies with known spectroscopic redshift prior to SN discovery to the total number of SN hosts). Of the 512 host galaxies with SNe Ia, 227 had previously known spectroscopic redshifts, yielding an RCF estimate of 44%{+/-}4%. The RCF decreases with increasing distance and decreasing galaxy luminosity (for z<0.05, or ~200Mpc, RCF~0.6). Prospects for dramatically increasing the RCF are limited to new multifiber spectroscopic instruments or wide-field narrowband surveys. Existing galaxy redshift catalogs are only ~50% complete at r~16.9mag. Pushing this limit several magnitudes deeper will pay huge dividends when searching for electromagnetic counterparts to gravitational wave events or sources of ultra-high-energy cosmic rays or neutrinos.
8443. ZYJHK photometry in Pleiades
ID:
ivo://CDS.VizieR/J/MNRAS/380/712
Title:
ZYJHK photometry in Pleiades
Short Name:
J/MNRAS/380/712
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a deep wide-field near-infrared survey of 12deg^2^ of the Pleiades conducted as part of the United Kingdom Infrared Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS) Galactic Cluster Survey (GCS). We have extracted over 340 high-probability proper motion (PM) members down to 0.03M_{sun}_ using a combination of UKIDSS photometry and PM measurements obtained by cross-correlating the GCS with data from the Two Micron All Sky Survey, the Isaac Newton Telescope and the Canada-France-Hawaii Telescope. Additionally, we have unearthed 73 new candidate brown dwarf (BD) members on the basis of five-band UKIDSS photometry alone. We have identified 23 substellar multiple system candidates out of 63 candidate BDs from the (Y-K, Y) and (J-K, J) colour-magnitude diagrams, yielding a binary frequency of 2844 per cent in the 0.075-0.030M_{sun}_ mass range.
8444. ZYJHK photometry in Upper Sco
ID:
ivo://CDS.VizieR/J/MNRAS/374/372
Title:
ZYJHK photometry in Upper Sco
Short Name:
J/MNRAS/374/372
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present first results from a deep (J=18.7), wide-field (6.5deg^2^) infrared (ZY JHK) survey in the Upper Sco association conducted within the science verification phase of the United Kingdom Infrared Telescope Infrared Deep Sky Survey Galactic Cluster Survey (GCS). Cluster members define a sequence well separated from field stars in the (Z-J, Z) colour-magnitude diagram. We have selected a total of 164 candidates with J =10.5-8.7mag from the (Z-J, Z) and (Y-J, Y) diagrams. We further investigated the location of those candidates in the other colour-magnitude and colour-colour diagrams to weed out contaminants. The cross-correlation of the GCS catalogue with the Two-Micron All-Sky Survey data base confirms the membership of 116 photometric candidates down to 20 Jupiter masses as they lie within a 2 circle centred on the association mean motion. The final list of cluster members contains 129 sources with masses between 0.3 and 0.007M_{sun}_.
8445. ZYJHK survey of Upper Sco association
ID:
ivo://CDS.VizieR/J/MNRAS/373/95
Title:
ZYJHK survey of Upper Sco association
Short Name:
J/MNRAS/373/95
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a 9.3-deg^2^ infrared (ZYJHK) survey in the Upper Scorpius association extracted from the UKIRT Infrared Deep Sky Survey (UKIDSS) Galactic Cluster Survey Early Data Release (Dye et al., 2006MNRAS.372.1227D). We have selected a total of 112 candidates from the (Z-J, Z) colour-magnitude diagram over the Z=12.5-20.5 magnitude range, corresponding to M=0.25-0.01M_{sun}_ at an age of 5Myr and a distance of 145pc. Additional photometry in J and K filters revealed most of them as reddened stars, leaving 32 possible members. Among them, 15 have proper motion consistent with higher-mass members from Hipparcos and optical spectra with strong H{alpha} in emission and weak gravity features. We have also extracted two lower-mass candidate members for which no optical spectra are in hand. Three members exhibit strong H{alpha} equivalent widths (>20{AA}), suggesting that they could still undergo accretion, whereas two other dwarfs show signs of chromospheric activity. The likelihood of the binarity of a couple of new stellar and substellar members is discussed as well.
8446. ZZ Ceti white dwarfs and candidates in Gaia survey
ID:
ivo://CDS.VizieR/J/AJ/160/252
Title:
ZZ Ceti white dwarfs and candidates in Gaia survey
Short Name:
J/AJ/160/252
Date:
09 Mar 2022 22:00:00
Publisher:
CDS
Description:
The Gaia satellite recently released parallax measurements for ~260000 high-confidence white dwarf candidates, allowing for precise measurements of their physical parameters. By combining these parallaxes with Pan-STARRS and u-band photometry, we measured the effective temperature and stellar mass for all white dwarfs in the Northern Hemisphere within 100pc of the Sun, and identified a sample of ZZ-Ceti white dwarf candidates within the so-called instability strip. We acquired high-speed photometric observations for 90 candidates using the PESTO camera attached to the 1.6m telescope at the Mont-Megantic Observatory. We report the discovery of 38 new ZZ-Ceti stars, including two very rare ultramassive pulsators. We also identified five possibly variable stars within the strip, in addition to 47 objects that do not appear to show any photometric variability. However, several of those could be variable with an amplitude below our detection threshold, or could be located outside the instability strip due to errors in their photometric parameters. In the light of our results, we explore the trends of the dominant period and amplitude in the M--Teff plane, and briefly discuss the question of the purity of the ZZ-Ceti instability strip (i.e., a region devoid of non-variable stars).
8447. ZZ Cyg times of minima
ID:
ivo://CDS.VizieR/J/other/NewA/37.48
Title:
ZZ Cyg times of minima
Short Name:
J/other/NewA/37.
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new photometry of the eclipsing binary ZZ Cyg. From all accumulated eclipsing times, we constructed the (O-C) curve, which can be described by a downward parabola with a possible light-time orbit. The period decrease rate is source dP/dt=-5.73(+/-0.18)d/yr. The modulated period, semi-amplitude and eccentricity for the light-time orbit are Pmod=71.4(+/-1.1)yr, A=0.0071(+/-0.0005)day and e=0.420(+/-0.053), respectively. After removing effects of the magnetic activity, this kind of cyclic oscillation may be attributed to light-time effect via an additional companion. By using the W-D code, the photometric model was updated, which identified that ZZ Cyg is a near-contact binary. We find that a hot spot may occur on the primary that explains the asymmetric light curve. The secular period decrease may possibly cause the fill-out factor of the primary to increase. Finally it will finally fill its Roche lobe. This kind of binary, ZZ Cyg, may evolve into contact binary star.