- ID:
- ivo://CDS.VizieR/J/ApJ/669/424
- Title:
- H2O maser emissions of IRAS 19134+2131
- Short Name:
- J/ApJ/669/424
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the Very Long Baseline Array at six epochs, we have observed H_2_O maser emission in the preplanetary nebula IRAS 19134+2131 (I19134), in which the H_2_O maser spectrum has two groups of emission features separated in radial velocity by ~100km/s. We also obtained optical images of I19134 with the Hubble Space Telescope to locate the bipolar reflection nebula in this source for the first time.
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- ID:
- ivo://CDS.VizieR/J/ApJ/871/63
- Title:
- How to constrain your M dwarf. II. Nearby binaries
- Short Name:
- J/ApJ/871/63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The mass-luminosity relation for late-type stars has long been a critical tool for estimating stellar masses. However, there is growing need for both a higher-precision relation and a better understanding of systematic effects (e.g., metallicity). Here we present an empirical relationship between M_Ks_ and M_*_ spanning 0.075M_{sun}_<M_*_<0.70M_{sun}_. The relation is derived from 62 nearby binaries, whose orbits we determine using a combination of near infra-red (Keck/NIRC2) imaging, archival adaptive optics data, and literature astrometry. From their orbital parameters, we determine the total mass of each system, with a precision better than 1% in the best cases. We use these total masses, in combination with resolved Ks magnitudes and system parallaxes, to calibrate the M_Ks_-M_*_ relation. The resulting posteriors can be used to determine masses of single stars with a precision of 2%-3%, which we confirm by testing the relation on stars with individual dynamical masses from the literature. The precision is limited by scatter around the best-fit relation beyond measured M_*_ uncertainties, perhaps driven by intrinsic variation in the M_Ks_-M_*_ relation or underestimated uncertainties in the input parallaxes. We find that the effect of [Fe/H] on the M_Ks_-M_*_ relation is likely negligible for metallicities in the solar neighborhood (0.0%{+/-}2.2% change in mass per dex change in [Fe/H]). This weak effect is consistent with predictions from the Dartmouth Stellar Evolution Database, but inconsistent with those from modules for experiments in stellar astrophysics (MESA) Isochrones and Stellar Tracks (MIST) (at 5{sigma}). A sample of binaries with a wider range of abundances will be required to discern the importance of metallicity in extreme populations (e.g., in the Galactic halo or thick disk).
- ID:
- ivo://CDS.VizieR/J/ApJ/859/38
- Title:
- HST grism obs. of CARLA galaxy cluster candidates
- Short Name:
- J/ApJ/859/38
- Date:
- 08 Mar 2022 13:56:29
- Publisher:
- CDS
- Description:
- We report spectroscopic results from our 40-orbit Hubble Space Telescope slitless grism spectroscopy program observing the 20 densest Clusters Around Radio-Loud AGN (CARLA) candidate galaxy clusters at 1.4<z<2.8. These candidate rich structures, among the richest and most distant known, were identified on the basis of [3.6]-[4.5] color from a 408hr multi-cycle Spitzer program targeting 420 distant radio-loud AGN. We report the spectroscopic confirmation of 16 distant structures at 1.4<z<2.8 associated with the targeted powerful high-redshift radio-loud AGN. We also report the serendipitous discovery and spectroscopic confirmation of seven additional structures at 0.87<z<2.12 not associated with the targeted radio-loud AGN. We find that 10^10^-10^11^M_{sun}_ member galaxies of our confirmed CARLA structures form significantly fewer stars than their field counterparts at all redshifts within 1.4<=z<=2. We also observe higher star-forming activity in the structure cores up to z=2, finding similar trends as cluster surveys at slightly lower redshifts (1.0<z<1.5). By design, our efficient strategy of obtaining just two grism orbits per field only obtains spectroscopic confirmation of emission line galaxies. Deeper spectroscopy will be required to study the population of evolved, massive galaxies in these (forming) clusters. Lacking multi-band coverage of the fields, we adopt a very conservative approach of calling all confirmations "structures," although we note that a number of features are consistent with some of them being bona fide galaxy clusters. Together this survey represents a unique and large homogenous sample of spectroscopically confirmed structures at high redshifts, potentially more than doubling the census of confirmed, massive clusters at z>1.4.
- ID:
- ivo://CDS.VizieR/J/MNRAS/417/114
- Title:
- HST/NICMOS Galactic Center survey catalogue
- Short Name:
- J/MNRAS/417/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our Hubble Space Telescope/Near-Infrared Camera and Multi-Object Spectrometer (HST/NICMOS) Paschen {alpha} survey of the Galactic Centre, first introduced by Wang et al. (2010MNRAS.402..895W), provides a uniform, panoramic, high-resolution map of stars and an ionized diffuse gas in the central 416arcmin^2^ of the Galaxy. This survey was carried out with 144 HST orbits using two narrow-band filters at 1.87 and 1.90um in NICMOS Camera 3. In this paper, we describe in detail the data reduction and mosaicking procedures followed, including background level matching and astrometric corrections. We have detected ~570000 near-infrared (near-IR) sources using the 'starfinder' software and are able to quantify photometric uncertainties of the detections.
- ID:
- ivo://CDS.VizieR/J/ApJ/900/183
- Title:
- HST NIR grism sp. of strong-lensing galaxy clusters
- Short Name:
- J/ApJ/900/183
- Date:
- 15 Feb 2022 11:31:32
- Publisher:
- CDS
- Description:
- We present the hitherto largest sample of gas-phase metallicity radial gradients measured at sub-kpc resolution in star-forming galaxies in the redshift range of 1.2<z<=2.3. These measurements are enabled by the synergy of slitless spectroscopy from the Hubble Space Telescope near-infrared channels and the lensing magnification from foreground galaxy clusters. Our sample consists of 76 galaxies with stellar mass ranging from 10^7^ to 10^10^M_{sun}, an instantaneous star formation rate in the range of [1,100]M_{sun}_/yr, and global metallicity [1/12,2] of solar. At a 2{sigma} confidence level, 15/76 galaxies in our sample show negative radial gradients, whereas 7/76 show inverted gradients. Combining ours and all other metallicity gradients obtained at a similar resolution currently available in the literature, we measure a negative mass dependence of {Delta}log(O/H)/{Delta}r[dex/kpc]=(-0.020+/-0.007)+(-0.016+/-0.008) log(M_*_/10^9.4^M_{sun}_), with the intrinsic scatter being {sigma}=0.060+/-0.006 over 4 orders of magnitude in stellar mass. Our result is consistent with strong feedback, not secular processes, being the primary governor of the chemostructural evolution of star-forming galaxies during the disk mass assembly at cosmic noon. We also find that the intrinsic scatter of metallicity gradients increases with decreasing stellar mass and increasing specific star formation rate. This increase in the intrinsic scatter is likely caused by the combined effect of cold-mode gas accretion and merger-induced starbursts, with the latter more predominant in the dwarf mass regime of M_*_<~10^9^M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/ApJ/779/137
- Title:
- HST NIR spectroscopy of ISCS z>1 galaxy clusters
- Short Name:
- J/ApJ/779/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Hubble Space Telescope near-IR spectroscopy for 18 galaxy clusters at 1.0<z<1.5 in the IRAC Shallow Cluster Survey (ISCS). We use Wide Field Camera 3 grism data to spectroscopically identify H{alpha} emitters in both the cores of galaxy clusters as well as in field galaxies. We find a large cluster-to-cluster scatter in the star formation rates within a projected radius of 500kpc, and many of our clusters (~60%) have significant levels of star formation within a projected radius of 200kpc. A stacking analysis reveals that dust reddening in these star-forming galaxies is positively correlated with stellar mass and may be higher in the field than the cluster at a fixed stellar mass. This may indicate a lower amount of gas in star-forming cluster galaxies than in the field population. Also, H{alpha} equivalent widths of star-forming galaxies in the cluster environment are still suppressed below the level of the field. This suppression is most significant for lower mass galaxies (logM_*_<10.0M_{sun}_). We therefore conclude that environmental effects are still important at 1.0<z<1.5 for star-forming galaxies in galaxy clusters with logM_*_<~10.0M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/ApJ/876/85
- Title:
- HST observations for LMC Cepheids
- Short Name:
- J/ApJ/876/85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an improved determination of the Hubble constant from Hubble Space Telescope (HST) observations of 70 long-period Cepheids in the Large Magellanic Cloud (LMC). These were obtained with the same WFC3 photometric system used to measure extragalactic Cepheids in the hosts of SNe Ia. Gyroscopic control of HST was employed to reduce overheads while collecting a large sample of widely separated Cepheids. The Cepheid period-luminosity relation provides a zero-point-independent link with 0.4% precision between the new 1.2% geometric distance to the LMC from detached eclipsing binaries (DEBs) measured by Pietrzynski+ (2019Natur.567..200P) and the luminosity of SNe Ia. Measurements and analysis of the LMC Cepheids were completed prior to knowledge of the new DEB LMC distance. Combined with a refined calibration of the count-rate linearity of WFC3-IR with 0.1% precision, these three improved elements together reduce the overall uncertainty in the geometric calibration of the Cepheid distance ladder based on the LMC from 2.5% to 1.3%. Using only the LMC DEBs to calibrate the ladder, we find H_0_=74.22+/-1.82km/s/Mpc including systematic uncertainties, 3% higher than before for this particular anchor. Combining the LMC DEBs, masers in NGC 4258, and Milky Way parallaxes yields our best estimate: H_0_=74.03+/-1.42km/s/Mpc, including systematics, an uncertainty of 1.91%-15% lower than our best previous result. Removing any one of these anchors changes H0 by less than 0.7%. The difference between H0 measured locally and the value inferred from Planck CMB and {Lambda}CDM is 6.6+/-1.5km/s/Mpc or 4.4{sigma} (P=99.999% for Gaussian errors) in significance, raising the discrepancy beyond a plausible level of chance. We summarize independent tests showing that this discrepancy is not attributable to an error in any one source or measurement, increasing the odds that it results from a cosmological feature beyond {Lambda}CDM.
- ID:
- ivo://CDS.VizieR/J/ApJ/730/119
- Title:
- HST/WFC3 observations of Cepheids in SN Ia hosts
- Short Name:
- J/ApJ/730/119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) to determine the Hubble constant from optical and infrared observations of over 600 Cepheid variables in the host galaxies of eight recent Type Ia supernovae (SNe Ia), providing the calibration for a magnitude-redshift relation based on 253 SNe Ia.
- ID:
- ivo://CDS.VizieR/J/ApJ/810/42
- Title:
- Hydrogen RRL parameters of H II regions
- Short Name:
- J/ApJ/810/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- H II regions are the ionized spheres surrounding high-mass stars. They are ideal targets for tracing Galactic structure because they are predominantly found in spiral arms and have high luminosities at infrared and radio wavelengths. In the Green Bank Telescope H II Region Discovery Survey (GBT HRDS), we found that >30% of first Galactic quadrant H II regions have multiple hydrogen radio recombination line (RRL) velocities, which makes determining their Galactic locations and physical properties impossible. Here we make additional GBT RRL observations to determine the discrete H II region velocity for all 117 multiple-velocity sources within 18{deg}<l<65{deg}. The multiple-velocity sources are concentrated in the zone 22{deg}<l<32{deg}, coinciding with the largest regions of massive star formation, which implies that the diffuse emission is caused by leaked ionizing photons. We combine our observations with analyses of the electron temperature, molecular gas, and carbon recombination lines to determine the source velocities for 103 discrete H II regions (88% of the sample). With the source velocities known, we resolve the kinematic distance ambiguity for 47 regions, and thus determine their heliocentric distances.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/3674
- Title:
- IC 348 circumstellar discs ALMA data
- Short Name:
- J/MNRAS/478/3674
- Date:
- 10 Dec 2021 00:10:52
- Publisher:
- CDS
- Description:
- We present a 1.3mm continuum survey of the young (2-3Myr) stellar cluster IC 348 that lies at a distance of 310pc and is dominated by low-mass stars (M*~0.1-0.6M_{sun}_). We observed 136 Class II sources (discs that are optically thick in the infrared) at 0.8arcsec (200au) resolution with a 3{sigma} sensitivity of ~0.45mJy (M_dust_~1.3M_{Earth}_). We detect 40 of the targets and construct a mm-continuum luminosity function. We compare the disc mass distribution in IC 348 to those of younger and older regions, taking into account the dependence on stellar mass. We find a clear evolution in disc masses from 1 to 5-10Myr. The disc masses in IC 348 are significantly lower than those in Taurus (1-3Myr) and Lupus (1-3Myr), similar to those of Chamaleon I, (2-3Myr) and {sigma} Ori (3-5Myr) and significantly higher than in Upper Scorpiusrpius (5-10Myr). About 20 discs in our sample (~5 percent of the cluster members) have estimated masses (dust+gas)>1M_Jup_ and hence might be the precursors of giant planets in the cluster. Some of the most massive discs include transition objects with inner opacity holes based on their infrared Spectral Energy Distribution (SEDs). From a stacking analysis of the 96 non-detections, we find that these discs have a typical dust mass of just <=0.4M_{Earth}_, even though the vast majority of their infrared SEDs remain optically thick and show little signs of evolution. Such low-mass discs may be the precursors of the small rocky planets found by Kepler around M-type stars.
