- ID:
- ivo://CDS.VizieR/J/ApJ/848/37
- Title:
- HST UV-IR photometry in CLASH galaxy clusters
- Short Name:
- J/ApJ/848/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new method for photometering objects in galaxy clusters. We introduce a mode-filtering technique for removing spatially variable backgrounds, improving both detection and photometric accuracy (roughly halving the scatter in the red sequence compared to previous catalogs of the same clusters). This method is based on robustly determining the distribution of background pixel values and should provide comparable improvement in photometric analysis of any crowded fields. We produce new multiwavelength catalogs for the 25 CLASH cluster fields in all 16 bandpasses from the UV through the near-IR, as well as rest-frame magnitudes. A comparison with spectroscopic values from the literature finds a ~30% decrease in the redshift deviation from previously released CLASH photometry. This improvement in redshift precision, in combination with a detection scheme designed to maximize purity, yields a substantial upgrade in cluster member identification over the previous CLASH galaxy catalog. We construct luminosity functions for each cluster, reliably reaching depths of at least 4.5mag below M* in every case, and deeper still in several clusters. We measure M* , {alpha}, and their redshift evolution, assuming the cluster populations are coeval, and find little to no evolution of {alpha}{<~}-0.9<~{alpha}{<~}-0.8, and M* values consistent with passive evolution. We present a catalog of galaxy photometry, photometric and spectroscopic redshifts, and rest-frame photometry for the full fields of view of all 25 CLASH clusters. Not only will our new photometric catalogs enable new studies of the properties of CLASH clusters, but mode-filtering techniques, such as those presented here, should greatly enhance the data quality of future photometric surveys of crowded fields.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/391/857
- Title:
- HST UV,V,I photometry of NGC7673 star clusters
- Short Name:
- J/A+A/391/857
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the star cluster system in the starburst galaxy NGC 7673 using archival Hubble Space Telescope WFPC2 broad-band images. For the first time we are able to examine the internal structures of the prominent optical clumps in this galaxy. The clumps are composed of young stars, 16-33% of which are in bright star clusters. We identify 268 star cluster candidates in both the F555W and F814W images, and 50 clusters with the F255W filter. These data allow us to estimate ages and masses using color-magnitude and two-color diagrams for our sample. We find a population of young, <6Myr clusters located throughout the galaxy with concentrations in the clumps. Star cluster mass estimates are 5-50x10^4^M_{sun}_ for the brightest objects. The starburst remains active in physically well-separated regions, indicating a widespread starburst trigger. We discuss clump lifetimes, their implications for the future evolution of NGC 7673, and possible relationships to high redshift starbursts.
- ID:
- ivo://CDS.VizieR/J/A+A/473/429
- Title:
- HST VI photometry of Bol 514 in M31
- Short Name:
- J/A+A/473/429
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the density profile of the remote M 31 globular cluster B514, obtained from HST/ACS observations.
- ID:
- ivo://CDS.VizieR/J/A+A/483/769
- Title:
- HST VI photometry of 3 globulars in M31
- Short Name:
- J/A+A/483/769
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We quantify the intrinsic width of the red giant branches of three massive globular clusters in M 31 in a search for metallicity spreads within these objects. We present HST/ACS observations of three massive clusters in M 31, G78, G213, and G280. A thorough description of the photometry extraction and calibration is presented. After derivation of the color-magnitude diagrams, we quantify the intrinsic width of the red giant branch of each cluster.
- ID:
- ivo://CDS.VizieR/J/ApJ/756/108
- Title:
- HST VI photometry of variable stars in Leo T
- Short Name:
- J/ApJ/756/108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from the first combined study of variable stars and star formation history (SFH) of the Milky Way "ultra-faint" dwarf (UFD) galaxy Leo T, based on F606W and F814W multi-epoch archive observations obtained with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. We have detected 14 variable stars in the galaxy. They include one fundamental-mode RR Lyrae star and 11 Anomalous Cepheids with periods shorter than 1 day, thus suggesting the occurrence of multiple star formation episodes in this UFD, of which one about 10 Gyr ago produced the RR Lyrae star. A new estimate of the distance to Leo T of 409^+29^_-27_kpc (distance modulus of 23.06+/-0.15mag) was derived from the galaxy's RR Lyrae star. Our V, V-I color-magnitude diagram (CMD) of Leo T reaches V~29mag and shows features typical of a galaxy in transition between dwarf irregular and dwarf spheroidal types. A quantitative analysis of the SFH, based on the comparison of the observed V, V-I CMD with the expected distribution of stars for different evolutionary scenarios, confirms that Leo T has a complex SFH dominated by two enhanced periods about 1.5 and 9 Gyr ago, respectively. The distribution of stars and gas shows that the galaxy has a fairly asymmetric structure.
- ID:
- ivo://CDS.VizieR/J/AJ/141/14
- Title:
- HST WFC3 ERS : emission-line galaxies
- Short Name:
- J/AJ/141/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present grism spectra of emission-line galaxies (ELGs) from 0.6 to 1.6um from the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope. These new infrared grism data augment previous optical Advanced Camera for Surveys G800L 0.6-0.95um grism data in GOODS-South from the PEARS program, extending the wavelength coverage well past the G800L red cutoff. The Early Release Science (ERS) grism field was observed at a depth of two orbits per grism, yielding spectra of hundreds of faint objects, a subset of which is presented here. ELGs are studied via the H{alpha}, [OIII], and [OII] emission lines detected in the redshift ranges 0.2~<z~<1.4, 1.2~<z~<2.2, and 2.0~<z~<3.3, respectively, in the G102 (0.8-1.1um; R~=210) and G141 (1.1-1.6um; R~=130) grisms.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/146
- Title:
- HST/WFC3 observations in HUDF and GOODS-S
- Short Name:
- J/ApJ/743/146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the high angular resolution in the near-infrared of the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope to determine YHVz color-color-selection criteria to identify and characterize 1.5<z<3.5 galaxies in the Hubble Ultra Deep Field 2009 (HUDF09) and Early Release Science (GOODS-South) fields. The WFC3 NIR images reveal galaxies at these redshifts that were undetected in the rest-frame UV HUDF/GOODS images, as well as true centers and regular disks in galaxies classified as highly irregular in rest-frame UV light. Across the 1.5<z<2.15 redshift range, regular disks are unveiled in the WFC3 images of ~25% of both intermediate and high mass galaxies, i.e., above 10^10^M_{sun}_. Meanwhile, galaxies maintaining diffuse and/or irregular morphologies in the rest-frame optical light - i.e., not yet dynamically settled - at these epochs are almost entirely restricted to masses below 10^11^M_{sun}_. In contrast at 2.25<z<3.5 these diffuse and/or irregular structures overwhelmingly dominate the morphological mix in both the intermediate and high mass regimes, while no regular disks, and only a small fraction (~25%) of smooth spheroids, are evident above 10^11^M_{sun}_. Strikingly, by 1.5<z<2.25 roughly two out of every three galaxies at the highest masses are spheroids. In our small sample, the fraction of star-forming galaxies at these mass scales decreases concurrently from ~60% to ~5%. If confirmed, this indicates that z~2 is the epoch of both the morphological transformation and quenching of star formation which assemble the first substantial population of massive ellipticals.
- 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/800/18
- Title:
- HST/WFC3 observations of z~7-8 galaxies in A2744
- Short Name:
- J/ApJ/800/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Exploiting the power of gravitational lensing, the Hubble Frontier Fields (HFF) program aims at observing six massive galaxy clusters to explore the distant universe far beyond the limits of blank field surveys. Using the complete Hubble Space Telescope observations of the first HFF cluster A2744, we report the detection of 50 galaxy candidates at z~7 and eight candidates at z~8 in a total survey area of 0.96arcmin^2^ in the source plane. Three of these galaxies are multiply imaged by the lensing cluster. Using an updated model of the mass distribution in the cluster we were able to calculate the magnification factor and the effective survey volume for each galaxy in order to compute the ultraviolet galaxy luminosity function (LF) at both redshifts 7 and 8. Our new measurements reliably extend the z~7 UV LF down to an absolute magnitude of M_UV_~-15.5. We find a characteristic magnitude of M_UV_^*^=-20.90_-0.73_^+0.90^mag and a faint-end slope {alpha}=-2.01_-0.28_^+0.20^, close to previous determinations in blank fields. We show here for the first time that this slope remains steep down to very faint luminosities of 0.01L^*^. Although prone to large uncertainties, our results at z~8 also seem to confirm a steep faint-end slope below 0.1L^*^. The HFF program is therefore providing an extremely efficient way to study the faintest galaxy populations at z>7 that would otherwise be inaccessible with current instrumentation. The full sample of six galaxy clusters will provide even better constraints on the buildup of galaxies at early epochs and their contribution to cosmic reionization.
- ID:
- ivo://CDS.VizieR/J/ApJ/826/56
- Title:
- HST/WFC3 obs. of Cepheids in SN Ia host gal.
- Short Name:
- J/ApJ/826/56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) to reduce the uncertainty in the local value of the Hubble constant from 3.3% to 2.4%. The bulk of this improvement comes from new near-infrared (NIR) observations of Cepheid variables in 11 host galaxies of recent type Ia supernovae (SNe Ia), more than doubling the sample of reliable SNe Ia having a Cepheid-calibrated distance to a total of 19; these in turn leverage the magnitude-redshift relation based on ~300 SNe Ia at z<0.15. All 19 hosts as well as the megamaser system NGC 4258 have been observed with WFC3 in the optical and NIR, thus nullifying cross-instrument zeropoint errors in the relative distance estimates from Cepheids. Other noteworthy improvements include a 33% reduction in the systematic uncertainty in the maser distance to NGC 4258, a larger sample of Cepheids in the Large Magellanic Cloud (LMC), a more robust distance to the LMC based on late-type detached eclipsing binaries (DEBs), HST observations of Cepheids in M31, and new HST-based trigonometric parallaxes for Milky Way (MW) Cepheids. We consider four geometric distance calibrations of Cepheids: (i) megamasers in NGC 4258, (ii) 8 DEBs in the LMC, (iii) 15 MW Cepheids with parallaxes measured with HST/FGS, HST/WFC3 spatial scanning and/or Hipparcos, and (iv) 2 DEBs in M31. The Hubble constant from each is 72.25+/-2.51, 72.04+/-2.67, 76.18+/-2.37, and 74.50+/-3.27km/s/Mpc, respectively. Our best estimate of H_0_=73.24+/-1.74km/s/Mpc combines the anchors NGC 4258, MW, and LMC, yielding a 2.4% determination (all quoted uncertainties include fully propagated statistical and systematic components). This value is 3.4{sigma} higher than 66.93+/-0.62km/s/Mpc predicted by {Lambda}CDM with 3 neutrino flavors having a mass of 0.06eV and the new Planck data, but the discrepancy reduces to 2.1{sigma} relative to the prediction of 69.3+/-0.7km/s/Mpc based on the comparably precise combination of WMAP+ACT+SPT+BAO observations, suggesting that systematic uncertainties in CMB radiation measurements may play a role in the tension. If we take the conflict between Planck high-redshift measurements and our local determination of H_0_ at face value, one plausible explanation could involve an additional source of dark radiation in the early universe in the range of {Delta}N_eff_~0.4-1. We anticipate further significant improvements in H_0_ from upcoming parallax measurements of long-period MW Cepheids.
