- ID:
- ivo://CDS.VizieR/J/ApJ/792/76
- Title:
- Lensed z~6-8 galaxies behind CLASH clusters
- Short Name:
- J/ApJ/792/76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We utilize 16 band Hubble Space Telescope (HST) observations of 18 lensing clusters obtained as part of the Cluster Lensing And Supernova survey with Hubble (CLASH) Multi-Cycle Treasury program to search for z ~ 6-8 galaxies. We report the discovery of 204, 45, and 13 Lyman-break galaxy candidates at z ~ 6, z ~ 7, and z ~ 8, respectively, identified from purely photometric redshift selections. This large sample, representing nearly an order of magnitude increase in the number of magnified star-forming galaxies at z ~ 6-8 presented to date, is unique in that we have observations in four WFC3/UVIS UV, seven ACS/WFC optical, and all five WFC3/IR broadband filters, which enable very accurate photometric redshift selections. We construct detailed lensing models for 17 of the 18 clusters to estimate object magnifications and to identify two new multiply lensed z >~ 6 candidates. The median magnifications over the 17 clusters are 4, 4, and 5 for the z ~ 6, z ~ 7, and z ~ 8 samples, respectively, over an average area of 4.5 arcmin^2^ per cluster. We compare our observed number counts with expectations based on convolving "blank" field UV luminosity functions through our cluster lens models and find rough agreement down to ~27 mag, where we begin to suffer significant incompleteness. In all three redshift bins, we find a higher number density at brighter observed magnitudes than the field predictions, empirically demonstrating for the first time the enhanced efficiency of lensing clusters over field surveys. Our number counts also are in general agreement with the lensed expectations from the cluster models, especially at z ~ 6, where we have the best statistics.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/723/1678
- Title:
- LensPerfect A1689 analysis
- Short Name:
- J/ApJ/723/1678
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a strong lensing (SL) mass model of A1689 which resolves substructures an estimated 25kpc across within the central ~400kpc diameter. We achieve this resolution by perfectly reproducing the observed (strongly lensed) input positions of 168 multiple images of 55 knots residing within 135 images of 42 galaxies. Our model makes no assumptions about light tracing mass, yet we reproduce the brightest visible structures with some slight deviations. A1689 remains one of the strongest known lenses on the sky, with an Einstein radius of R_E_=47.0+/-1.2" (143^+3^_-4_kpc) for a lensed source at z_s_=2. We find that a single Navarro-Frenk-White (NFW) or Sersic profile yields a good fit simultaneously (with only slight tension) to both our SL mass model and published weak lensing (WL) measurements at larger radius (out to the virial radius). Our SL model prefers slightly higher concentrations than previous SL models, bringing our SL+WL constraints in line with other recent derivations. Our results support those of previous studies which find A1689 has either an anomalously large concentration or significant extra mass along the line of sight (perhaps in part due to triaxiality).
- ID:
- ivo://CDS.VizieR/J/ApJ/718/530
- Title:
- Leo IV g- and r-band photometry
- Short Name:
- J/ApJ/718/530
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present MMT/Megacam imaging of the Leo IV dwarf galaxy in order to investigate its structure and star formation history, and to search for signs of association with the recently discovered Leo V satellite. Based on parameterized fits, we find that Leo IV is round, with {epsilon}<0.23 (at the 68% confidence limit) and a half-light radius of r_h_~130pc. Additionally, we perform a thorough search for extended structures in the plane of the sky and along the line of sight. We derive our surface brightness detection limit by implanting fake structures into our catalog with stellar populations identical to that of Leo IV. We show that we are sensitive to stream-like structures with surface brightness {mu}_r_<~29.6mag/arcsec^2^, and at this limit we find no stellar bridge between Leo IV (out to a radius of ~0.5kpc) and the recently discovered, nearby satellite Leo V. Using the color-magnitude fitting package StarFISH, we determine that Leo IV is consistent with a single age (~14Gyr), single metallicity ([Fe/H]~-2.3) stellar population, although we cannot rule out a significant spread in these values. We derive a luminosity of M_V_=-5.5+/-0.3. Studying both the spatial distribution and frequency of Leo IV's "blue plume" stars reveals evidence for a young (~2Gyr) stellar population which makes up ~2% of its stellar mass.
3464. Leo I VI photometry
- ID:
- ivo://CDS.VizieR/J/MNRAS/354/708
- Title:
- Leo I VI photometry
- Short Name:
- J/MNRAS/354/708
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present V and I photometry of a 9.4'x9.4' field centered on the dwarf spheroidal galaxy Leo I. The I magnitude of the tip of the Red Giant Branch is robustly estimated from two different datasets I^TRGB^=17.97 (^+0.05^_-0.03_). From this estimate, adopting [M/H]~-1.2 from the comparison of RGB stars with Galactic templates, we obtain a distance modulus (m-M)_0=22.02+/-0.13, corresponding to a distance D=254^+16^_-19_kpc.
- ID:
- ivo://CDS.VizieR/J/ApJ/812/158
- Title:
- Leo P RR Lyrae candidates & cumulative SFH
- Short Name:
- J/ApJ/812/158
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Leo P is a low-luminosity dwarf galaxy discovered through the blind HI Arecibo Legacy Fast ALFA survey. The HI and follow-up optical observations have shown that Leo P is a gas-rich dwarf galaxy with active star formation, an underlying older population, and an extremely low oxygen abundance. We have obtained optical imaging with the Hubble Space Telescope to two magnitudes below the red clump in order to study the evolution of Leo P. We refine the distance measurement to Leo P to be 1.62+/-0.15Mpc, based on the luminosity of the horizontal branch stars and 10 newly identified RR Lyrae candidates. This places the galaxy at the edge of the Local Group, ~0.4Mpc from Sextans B, the nearest galaxy in the NGC 3109 association of dwarf galaxies of which Leo P is clearly a member. The star responsible for ionizing the HII region is most likely an O7V or O8V spectral type, with a stellar mass >~25M_{sun}_. The presence of this star provides observational evidence that massive stars at the upper end of the initial mass function are capable of being formed at star formation rates as low as ~10^-5^M_{sun}_/yr. The best-fitting star formation history (SFH) derived from the resolved stellar populations of Leo P using the latest PARSEC models shows a relatively constant star formation rate over the lifetime of the galaxy. The modeled luminosity characteristics of Leo P at early times are consistent with low-luminosity dSph Milky Way satellites, suggesting that Leo P is what a low-mass dSph would look like if it evolved in isolation and retained its gas. Despite the very low mass of Leo P, the imprint of reionization on its SFHIs subtle at best, and consistent with being totally negligible. The isolation of Leo P, and the total quenching of star formation of Milky Way satellites of similar mass, implies that the local environment dominates the quenching of the Milky Way satellites.
- ID:
- ivo://CDS.VizieR/J/MNRAS/415/1479
- Title:
- LESS photometric redshift survey
- Short Name:
- J/MNRAS/415/1479
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive photometric redshifts from 17-band optical to mid-infrared photometry of 78 robust radio, 24um and Spitzer IRAC counterparts to 72 of the 126 submillimetre galaxies (SMGs) selected at 870um by LABOCA observations in the Extended Chandra Deep Field-South (ECDF-S). We test the photometric redshifts of the SMGs against the extensive archival spectroscopy in the ECDF-S.
- ID:
- ivo://CDS.VizieR/J/PASP/117/676
- Title:
- LHS faint proper-motion stars
- Short Name:
- J/PASP/117/676
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present low-resolution spectroscopic observations of faint proper-motion stars from the LHS Catalogue, concentrating on stars with m_r_>16.5 and {mu}>0.5"/yr. The present paper includes observations and spectral classifications for 294 M dwarfs, M subdwarfs (sdM), and extreme M subdwarfs (esdM). We also identify white dwarfs among the faintest LHS stars. We have cross-referenced this sample against the Two Micron All Sky Survey (2MASS) sources, and list data for the detected objects. We discuss stars of individual interest, as well as the characteristics of the overall sample. As expected, a significant number of the stars in this proper-motion-selected sample are halo subdwarfs, including an esdM dwarf, LHS 3481, that is likely to lie within 20pc of the Sun. None of the subdwarfs show H{alpha} emission.
- ID:
- ivo://CDS.VizieR/J/A+A/545/A85
- Title:
- LHS1070 photometry and spectroscopy
- Short Name:
- J/A+A/545/A85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- LHS 1070 is a nearby multiple system of low mass stars. It is an important source of information for probing the low mass end of the main sequence, down to the hydrogen-burning limit. The primary of the system is a mid-M dwarf and two components are late-M to early L dwarfs, at the star-brown dwarf transition. Hence LHS 1070 is a valuable object to understand the onset of dust formation in cool stellar atmospheres. This work aims at determining the fundamental stellar parameters of LHS 1070 and to test recent model atmospheres: BT-Dusty, BT-Settl, DRIFT, and MARCS models.
3469. LH 47 UVBRI photometry
- ID:
- ivo://CDS.VizieR/J/A+AS/123/455
- Title:
- LH 47 UVBRI photometry
- Short Name:
- J/A+AS/123/455
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table 3 lists the final photometric data of our observations. The UBVRI observations were done with the 1.54m Danish telescope at ESO on October 3rd and 4th, 1992. The CCD was ESO#28, a TEK 1024x1024 with a pixel size of 24mue corresponding to 0.377" per pixel. The total field of view is 6.4'x6.4'. A standard reduction was done with MIDAS and IRAF, the photometry was performed with DAOPHOT within IRAF. The images of Oct 4th have been calibrated using the calibration field around PG 0231+051 (Landolt 1992, Cat. <II/183>). The images of Oct 3rd have then been adopted to the system of Oct 4th. The final Table 3 lists 4613 stars with V and B-V information. In addition U-B is available for 1159 of these stars, V-R for 3519 and V-I for 2854 stars. Table 4 gives those stars from our field of view which are present in the MACS (Magellanic Catalogue of Stars; Tucholke et al. 1996, Cat. <I/221>). The table contains the MACS Id., our x and y position and our UBV photometry, and right ascension and declination from the MACS. These stars may serve to calculate an exact position for every star from Table 3 or to define a coordinate grid for comparison with other observations, such as radio or X-ray data.
- ID:
- ivo://CDS.VizieR/J/ApJ/871/108
- Title:
- Lick AGN monitoring project 2011: V band
- Short Name:
- J/ApJ/871/108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In Spring 2011, the Lick AGN Monitoring Project observed a sample of 15 bright, nearby Seyfert 1 galaxies in the V band as part of a reverberation mapping campaign. The observations were taken at six ground-based telescopes, including the West Mountain Observatory 0.91m telescope, the 0.76m Katzman Automatic Imaging Telescope, 0.6m Super-LOTIS (Livermore Optical Transient Imaging System) at Kitt Peak, the Palomar 60inch telescope, and the 2m Faulkes telescopes North and South. The V-band light curves measure the continuum variability of our sample of Seyferts on an almost daily cadence for 2-3 months. We use image-subtraction software to isolate the variability of the Seyfert nucleus from the constant V-band flux of the host galaxy for the most promising targets, and we adopt standard aperture photometry techniques for the targets with smaller levels of variability. These V-band light curves will be used, with measurements of the broad emission line flux, to measure supermassive black hole masses and to constrain the geometry and dynamics of the broad-line region through dynamical modeling techniques.
