- ID:
- ivo://CDS.VizieR/J/ApJ/812/39
- Title:
- Fluxes of NGG7793 & NGC4945 with GMOS-S
- Short Name:
- J/ApJ/812/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Gas-phase abundances in HII regions of two spiral galaxies, NGC7793 and NGC4945, have been studied to determine their radial metallicity gradients. We used the strong-line method to derive oxygen abundances from spectra acquired with GMOS-S, the multi-object spectrograph on the 8m Gemini South telescope. We found that NGC7793 has a well-defined gas-phase radial oxygen gradient of -0.321+/-0.112dexR_25_^-1^ (or -0.054+/-0.019dex/kpc) in the galactocentric range 0.17<R_G_/R_25_<0.82, not dissimilar from gradients calculated with direct abundance methods in galaxies of similar mass and morphology. We also determined a shallow radial oxygen gradient in NGC 4945, -0.253+/-0.149dexR_25_^-1^ (or -0.019+/-0.011dex/kpc) for 0.04<R_G_/R_25_<0.51, where the larger relative uncertainty derives mostly from the larger inclination of this galaxy. NGC 7793 and NGC 4945 have been selected for this study because they are similar, in mass and morphology, to M33 and the Milky Way, respectively. Since at zeroth order we expect the radial metallicity gradients to depend on mass and galaxy type, we compared our galaxies in the framework of radial metallicity models best suited for M33 and the Galaxy. We found a good agreement between M33 and NGC7793, pointing toward similar evolution for the two galaxies. We notice instead differences between NGC 4945 and the radial metallicity gradient model that best fits the Milky Way. We found that these differences are likely related to the presence of an active galactic nucleus combined with a bar in the central regions of NGC 4945, and to its interacting environment.
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- ID:
- ivo://CDS.VizieR/J/AJ/159/100
- Title:
- Flux & RVs of the dwarf G9-40 with K2 & HPF
- Short Name:
- J/AJ/159/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We validate the discovery of a 2-Earth-radii sub-Neptune-sized planet around the nearby high-proper-motion M2.5 dwarf G9-40 (EPIC212048748), using high-precision, near-infrared (NIR) radial velocity (RV) observations with the Habitable-zone Planet Finder (HPF), precision diffuser-assisted ground-based photometry with a custom narrowband photometric filter, and adaptive optics imaging. At a distance of d=27.9pc, G9-40b is the second-closest transiting planet discovered by K2 to date. The planet's large transit depth (~3500ppm), combined with the proximity and brightness of the host star at NIR wavelengths (J=10, K=9.2), makes G9-40b one of the most favorable sub-Neptune-sized planets orbiting an M dwarf for transmission spectroscopy with James Webb Space Telescope, ARIEL, and the upcoming Extremely Large Telescopes. The star is relatively inactive with a rotation period of ~29days determined from the K2 photometry. To estimate spectroscopic stellar parameters, we describe our implementation of an empirical spectral-matching algorithm using the high-resolution NIR HPF spectra. Using this algorithm, we obtain an effective temperature of Teff=3404{+/-}73K and metallicity of [Fe/H]=-0.08{+/-}0.13. Our RVs, when coupled with the orbital parameters derived from the transit photometry, exclude planet masses above 11.7M{Earth} with 99.7% confidence assuming a circular orbit. From its radius, we predict a mass of M=5.0_-1.9_^+3.8^M_{Earth}_ and an RV semiamplitude of K=4.1_-1.6_^+3.1^m/s, making its mass measurable with current RV facilities. We urge further RV follow-up observations to precisely measure its mass, to enable precise transmission spectroscopic measurements in the future.
1193. FOCAT-S Catalogue
- ID:
- ivo://CDS.VizieR/I/195
- Title:
- FOCAT-S Catalogue
- Short Name:
- I/195
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is a new reduction of FOCAT-S photographic catalogue of southern stars. This reduction has to replace the preceding one. The differences from previous version are as follows: 1. The new version was sorted according right ascension of stars inside 10-degree declination zone; 2. New proper motions were calculated for all almost stars. New Astrographic Catalogue plate reduction was developed for this aim. The average rms of new FOCAT-S proper motions is 0.002 - 0.003 "/year; 3. The number of the Astrographic Catalogue star positions used for the proper motion calculation is added; 4. The magnitude (mag) and spectral type (Sp) columns were revised significantly: some errors were corrected; stars identified in C.S.I. catalogue have got Mag, Sp from this catalogue as it was in previous version. Other stars have got Mag, Sp from PPM-S catalogue. 5. The list of Durchmusterung star numbers was changed. Now it contains the Cape Photographic Durchmusterung (CPD) numbers for stars in [-90, -23] declination zones; Cordoba Durchmusterung (CoD) star numbers are used only if it was impossible to identify star in BD or CPD. Format of this column was changed also. 6. PPM catalogue star numbers were added.
- ID:
- ivo://CDS.VizieR/J/ApJ/891/3
- Title:
- Follow-up LCs of 2 Spitzer microlensing events
- Short Name:
- J/ApJ/891/3
- Date:
- 17 Jan 2022 00:32:54
- Publisher:
- CDS
- Description:
- We report the mass and distance measurements of two single-lens events from the 2017 Spitzer microlensing campaign. The ground-based observations yield the detection of finite-source effects, and the microlens parallaxes are derived from the joint analysis of ground-based observations and Spitzer observations. We find that the lens of OGLE-2017-BLG-1254 is a 0.60+/-0.03M_{sun}_ star with DLS=0.53+/-0.11kpc, where DLS is the distance between the lens and the source. The second event, OGLE-2017-BLG-1161, is subject to the known satellite parallax degeneracy, and thus is either a 0.51_-0.10_^+0.12^M_{sun}_ star with DLS=0.40+/-0.12kpc or a 0.38_-0.12_^+0.13^M_{sun} star with DLS=0.53+/-0.19kpc. Both of the lenses are therefore isolated stars in the Galactic bulge. By comparing the mass and distance distributions of the eight published Spitzer finite- source events with the expectations from a Galactic model, we find that the Spitzer sample is in agreement with the probability of finite-source effects occurring in single-lens events.
- ID:
- ivo://CDS.VizieR/J/ApJ/724/866
- Title:
- Follow-up observations of HAT-P-15
- Short Name:
- J/ApJ/724/866
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of HAT-P-15b, a transiting extrasolar planet in the "period valley," a relatively sparsely populated period regime of the known extrasolar planets. The host star, GSC 2883-01687, is a G5 dwarf with V=12.16. It has a mass of 1.01+/-0.04M_{sun}_, radius of 1.08+/-0.04R_{sun}_, effective temperature 5568+/-90K, and metallicity [Fe/H]=+0.22+/-0.08. The planetary companion orbits the star with a period P=10.863502+/-0.000027 days, transit epoch T_c_=2454638.56019+/-0.00048(BJD), and transit duration 0.2285+/-0.0015days. It has a mass of 1.946+/-0.066M_J_ and radius of 1.072+/-0.043R_J_ yielding a mean density of 1.96+/-0.22g/cm^3^. At an age of 6.8^+2.5^_-1.6_Gyr, the planet is H/He-dominated and theoretical models require about 2% (10M_{earth}_) worth of heavy elements to reproduce its measured radius. With an estimated equilibrium temperature of ~820K during transit, and ~1000K at occultation, HAT-P-15b is a potential candidate to study moderately cool planetary atmospheres by transmission and occultation spectroscopy.
- ID:
- ivo://CDS.VizieR/J/ApJ/826/144
- Title:
- Follow-up observations of SNIa ASASSN-14lp
- Short Name:
- J/ApJ/826/144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- On 2014 December 9.61, the All-sky Automated Survey for SuperNovae (ASAS-SN or "Assassin") discovered ASASSN-14lp just ~2 days after first light using a global array of 14cm diameter telescopes. ASASSN-14lp went on to become a bright supernova (V=11.94mag), second only to SN 2014J for the year. We present prediscovery photometry (with a detection less than a day after first light) and ultraviolet through near-infrared photometric and spectroscopic data covering the rise and fall of ASASSN-14lp for more than 100 days. We find that ASASSN-14lp had a broad light curve ({Delta}m_15_(B)=0.80+/-0.05), a B-band maximum at 2457015.82+/-0.03, a rise time of 16.94_-0.10_^+0.11^days, and moderate host-galaxy extinction (E(B-V)_host_=0.33+/-0.06). Using ASASSN-14lp, we derive a distance modulus for NGC 4666 of {mu}=30.8+/-0.2, corresponding to a distance of 14.7+/-1.5Mpc. However, adding ASASSN-14lp to the calibrating sample of Type Ia supernovae still requires an independent distance to the host galaxy. Finally, using our early-time photometric and spectroscopic observations, we rule out red giant secondaries and, assuming a favorable viewing angle and explosion time, any nondegenerate companion larger than 0.34R_{sun}_.
- ID:
- ivo://CDS.VizieR/J/ApJ/887/126
- Title:
- Follow-up obs. of the PSJ0147+4630 lens system
- Short Name:
- J/ApJ/887/126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Because follow-up observations of quadruple gravitational lens systems are of extraordinary importance for astrophysics and cosmology, we present single-epoch optical spectra and r-band light curves of PS J0147+4630. This recently discovered system mainly consists of four images ABCD of a background quasar around a foreground galaxy G that acts as a gravitational lens. First, we use long-slit spectroscopic data in the Gemini Observatory Archive and a multi-component fitting to accurately resolve the spectra of A, D, and G. The spectral profile of G resembles that of an early-type galaxy at a redshift of 0.678+/-0.001, which is about 20% higher than the previous estimate. Additionally, the stellar velocity dispersion is measured to ~5% precision. Second, our early r-band monitoring with the Liverpool Telescope leads to accurate light curves of the four quasar images. Adopting time delays predicted by the lens model, the new lens redshift, and a standard cosmology, we report the detection of microlensing variations in C and D as large as ~0.1mag on timescales of a few hundred days. We also estimate an actual delay between A and B of a few days (B is leading), which demonstrates the big potential of optical monitoring campaigns of PS J0147+4630.
- ID:
- ivo://CDS.VizieR/J/ApJ/872/135
- Title:
- Follow-up obs. of the type IIn SN KISS15s
- Short Name:
- J/ApJ/872/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of an SN 1988Z-like type IIn supernova KISS15s found in a low-mass star-forming galaxy at redshift z=0.038 during the course of the Kiso Supernova Survey (KISS). KISS15s shows long-duration optical continuum and emission line light curves, indicating that KISS15s is powered by a continuous interaction between the expanding ejecta and dense circumstellar medium (CSM). The H{alpha} emission line profile can be decomposed into four Gaussians of narrow, intermediate, blueshifted intermediate, and broad velocity width components, with a full width at half maximum of <~100, ~2000, and ~14000km/s for the narrow, intermediate, and broad components, respectively. The presence of the blueshifted intermediate component, of which the line-of-sight velocity relative to the systemic velocity is about -5000km/s, suggests that the ejecta-CSM interaction region has an inhomogeneous morphology and anisotropic expansion velocity. We found that KISS15s shows increasing infrared continuum emission, which can be interpreted as hot dust thermal emission of T~1200K from newly formed dust in a cool, dense shell in the ejecta-CSM interaction region. The progenitor mass-loss rate, inferred from bolometric luminosity, is dM/dt~0.4M_{sun}_/yr ({nu}_w_/40km/s), where {nu}_w_ is the progenitor's stellar wind velocity. This implies that the progenitor of KISS15s was a red supergiant star or a luminous blue variable that had experienced a large mass loss in the centuries before the explosion.
- ID:
- ivo://CDS.VizieR/J/ApJ/890/131
- Title:
- Follow-up of candidate counterparts of S190814bv
- Short Name:
- J/ApJ/890/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- On 2019 August 14, the Advanced LIGO and Virgo interferometers detected the high-significance gravitational wave (GW) signal S190814bv. The GW data indicated that the event resulted from a neutron star-black hole (NSBH) merger, or potentially a low-mass binary BH merger. Due to the low false-alarm rate and the precise localization (23deg^2^ at 90%), S190814bv presented the community with the best opportunity yet to directly observe an optical/near-infrared counterpart to an NSBH merger. To search for potential counterparts, the GROWTH Collaboration performed real-time image subtraction on six nights of public Dark Energy Camera images acquired in the 3 weeks following the merger, covering >98% of the localization probability. Using a worldwide network of follow-up facilities, we systematically undertook spectroscopy and imaging of optical counterpart candidates. Combining these data with a photometric redshift catalog, we ruled out each candidate as the counterpart to S190814bv and placed deep, uniform limits on the optical emission associated with S190814bv. For the nearest consistent GW distance, radiative transfer simulations of NSBH mergers constrain the ejecta mass of S190814bv to be M_ej_<0.04M_{sun}_ at polar viewing angles, or M_ej_<0.03M_{sun}_ if the opacity is {kappa}<2cm^2^g^-1^. Assuming a tidal deformability for the NS at the high end of the range compatible with GW170817 results, our limits would constrain the BH spin component aligned with the orbital momentum to be {chi}<0.7 for mass ratios Q<6, with weaker constraints for more compact NSs.
- ID:
- ivo://CDS.VizieR/J/ApJ/831/133
- Title:
- Follow-up of probable young star ASASSN-15qi
- Short Name:
- J/ApJ/831/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Outbursts on young stars are usually interpreted as accretion bursts caused by instabilities in the disk or the star-disk connection. However, some protostellar outbursts may not fit into this framework. In this paper, we analyze optical and near-infrared spectra and photometry to characterize the 2015 outburst of the probable young star ASASSN-15qi. The ~3.5mag brightening in the V band was sudden, with an unresolved rise time of less than one day. The outburst decayed exponentially by 1mag for 6 days and then gradually back to the pre-outburst level after 200 days. The outburst is dominated by emission from ~10000K gas. An explosive release of energy accelerated matter from the star in all directions, seen in a spectacular cool, spherical wind with a maximum velocity of 1000km/s. The wind and hot gas both disappeared as the outburst faded and the source returned to its quiescent F-star spectrum. Nebulosity near the star brightened with a delay of 10-20 days. Fluorescent excitation of H_2_ is detected in emission from vibrational levels as high as v=11, also with a possible time delay in flux increase. The mid-infrared spectral energy distribution does not indicate the presence of warm dust emission, though the optical photospheric absorption and CO overtone emission could be related to a gaseous disk. Archival photometry reveals a prior outburst in 1976. Although we speculate about possible causes for this outburst, none of the explanations are compelling.
