- ID:
- ivo://CDS.VizieR/J/A+A/604/A4
- Title:
- CALIFA galaxies observational hints
- Short Name:
- J/A+A/604/A4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- According to numerical simulations, stars are not always kept at their birth galactocentric distances but migrate. The importance of this radial migration in shaping galactic light distributions is still unclear. However, if it is indeed important, galaxies with different surface brightness (SB) profiles must display differences in their stellar population properties. We investigate the role of radial migration on the light distribution and the radial stellar content by comparing the inner colour, age and metallicity gradients for galaxies with different SB profiles. We define these inner parts avoiding the bulge and bar regions and up to around three disc scale lengths (type I, pure exponential) or the break radius (type II, downbending; type III, upbending). We analyse 214 spiral galaxies from the CALIFA survey covering different SB profiles. We make use of GASP2D and SDSS data to characterise their light distribution and obtain colour profiles. The stellar age and metallicity profiles are computed using a methodology based on full-spectrum fitting techniques (pPXF, GANDALF, and STECKMAP) to the IFS CALIFA data. The distributions of the colour, stellar age and stellar metallicity gradients in the inner parts for galaxies displaying different SB profiles are unalike as suggested by Kolmogorov-Smirnov and Anderson-Darling tests. We find a trend in which type II galaxies show the steepest profiles of all and type III the shallowest, with type I galaxies displaying an intermediate behaviour. These results are consistent with a scenario in which radial migration is more efficient for type III galaxies than for type I systems with type II galaxies presenting the lowest radial migration efficiency. In such scenario, radial migration mixes the stellar content flattening the radial stellar properties and shaping different SB profiles. However, in sight of these results we cannot further quantify its importance in shaping spiral galaxies, and other processes such as recent star formation or satellite accretion might play a role.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/848/87
- Title:
- CALIFA SFRs. II. Bulges, bars & disks
- Short Name:
- J/ApJ/848/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We estimate the current extinction-corrected H{alpha} star formation rate (SFR) of the different morphological components that shape galaxies (bulges, bars, and disks). We use a multicomponent photometric decomposition based on Sloan Digital Sky Survey imaging to Calar Alto Legacy Integral Field Area Integral Field Spectroscopy (IFS) datacubes for a sample of 219 galaxies. This analysis reveals an enhancement of the central SFR and specific SFR (sSFR = SFR/M*) in barred galaxies. Along the main sequence, we find that more massive galaxies in total have undergone efficient suppression (quenching) of their star formation, in agreement with many studies. We discover that more massive disks have had their star formation quenched as well. We evaluate which mechanisms might be responsible for this quenching process. The presence of type 2 AGNs plays a role at damping the sSFR in bulges and less efficiently in disks. Also, the decrease in the sSFR of the disk component becomes more noticeable for stellar masses around 10^10.5^M_{sun}_; for bulges, it is already present at ~10^9.5^M_{sun}_. The analysis of the line- of-sight stellar velocity dispersions ({sigma}) for the bulge component and of the corresponding Faber-Jackson relation shows that AGNs tend to have slightly higher {sigma} values than star-forming galaxies for the same mass. Finally, the impact of environment is evaluated by means of the projected galaxy density, {Sigma}5. We find that the SFR of both bulges and disks decreases in intermediate- to high-density environments. This work reflects the potential of combining IFS data with 2D multicomponent decompositions to shed light on the processes that regulate the SFR.
- ID:
- ivo://CDS.VizieR/J/AJ/157/229
- Title:
- CALSPEC: WFC3 infrared grism spectrophotometry
- Short Name:
- J/AJ/157/229
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The collections of spectral energy distributions (SEDs) in the Hubble Space Telescope (HST) CALSPEC database are augmented by 19 infrared (IR) SEDs from Wide Field Camera 3 (WFC3) IR grism spectra. Together, the two IR grisms, G102 and G141, cover the 0.8-1.7 {mu}m range with resolutions of R=200 and 150, respectively. These new WFC3 SEDs overlap existing CALSPEC Space Telescope Imaging Spectrograph (STIS) standard star flux distributions at 0.8-1 {mu}m with agreement to ~<1%. Some CALSPEC standards already have near-IR camera and multi-object spectrogragh (NICMOS) SEDs; but in their overlap region at 0.8-1.7 {mu}m, the WFC3 data have better wavelength accuracy, better spectral resolution, better repeatability, and, consequently, better flux distributions of ~1% accuracy in our CALSPEC absolute flux SEDs versus ~2% for NICMOS. With the improved SEDs in the WFC3 range, the modeled extrapolations to 32 {mu}m for the James Webb Space Telescope flux standards begin to lose precision longward of the 1.7 {mu}m WFC3 limit, instead of at the 1.0-{mu}m-long wavelength limit for STIS. For example, the extrapolated IR flux longward of 1.7 {mu}m for 1808347 increases by ~1% for the model fit to the data with WFC3, instead of just to the STIS SED alone.
- ID:
- ivo://CDS.VizieR/J/AJ/153/157
- Title:
- Candidate ICRF flat-spectrum radio sources. III.
- Short Name:
- J/AJ/153/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In extending our spectroscopic program, which targets sources drawn from the International Celestial Reference Frame (ICRF) Catalog, we have obtained spectra for ~160 compact, flat-spectrum radio sources and determined redshifts for 112 quasars and radio galaxies. A further 14 sources with featureless spectra have been classified as BL Lac objects. Spectra were obtained at three telescopes: the 3.58m European Southern Observatory New Technology Telescope, and the two 8.2m Gemini telescopes in Hawaii and Chile. While most of the sources are powerful quasars, a significant fraction of radio galaxies is also included from the list of non-defining ICRF radio sources.
- ID:
- ivo://CDS.VizieR/J/MNRAS/472/772
- Title:
- Candidate LAEs at z=5.7 and z=6.6
- Short Name:
- J/MNRAS/472/772
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopic follow-up of candidate luminous Ly{alpha} emitters (LAEs) at z=5.7-6.6 in the SA22 field with VLT/X-SHOOTER. We confirm two new luminous LAEs at z=5.676 (SR6) and z=6.532 (VR7), and also present HST follow-up of both sources. These sources have luminosities L_Ly {alpha}_~=3x10^43^erg/s, very high rest-frame equivalent widths of EW_0_>=200{AA} and narrow Ly{alpha} lines (200-340km/s). VR7 is the most UV-luminous LAE at z>6.5, with M_1500_=-22.5, even brighter in the UV than CR7. Besides Ly{alpha}, we do not detect any other rest-frame UV lines in the spectra of SR6 and VR7, and argue that rest-frame UV lines are easier to observe in bright galaxies with low Ly{alpha} equivalent widths. We confirm that Ly{alpha} line widths increase with Ly{alpha} luminosity at z=5.7, while there are indications that Ly{alpha} lines of faint LAEs become broader at z=6.6, potentially due to reionization. We find a large spread of up to 3 dex in UV luminosity for >L* LAEs, but find that the Ly{alpha} luminosity of the brightest LAEs is strongly related to UV luminosity at z=6.6. Under basic assumptions, we find that several LAEs at z~=6-7 have Ly{alpha} escape fractions >=100 per cent, indicating bursty star formation histories, alternative Ly{alpha} production mechanisms, or dust attenuating Ly{alpha} emission differently than UV emission. Finally, we present a method to compute {xi}_ion_, the production efficiency of ionizing photons, and find that LAEs at z~=6-7 have high values of log_10_({xi}_ion_/Hz/erg)~=25.51+/-0.09 that may alleviate the need for high Lyman-Continuum escape fractions required for reionization.
- ID:
- ivo://CDS.VizieR/J/ApJ/823/11
- Title:
- Candidate Ly{alpha} emitting galaxies at z~3.8
- Short Name:
- J/ApJ/823/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new observations of the field containing the z=3.786 protocluster PC 217.96+32.3. We confirm that it is one of the largest known and most overdense high-redshift structures. Such structures are rare even in the largest cosmological simulations. We used the Mayall/MOSAIC1.1 imaging camera to image a 1.2x0.6{deg} area (~150x75 comoving Mpc) surrounding the protocluster's core and discovered 165 candidate Ly{alpha} emitting galaxies (LAEs) and 788 candidate Lyman Break galaxies (LBGs). There are at least two overdense regions traced by the LAEs, the largest of which shows an areal overdensity in its core (i.e., within a radius of 2.5 comoving Mpc) of 14+/-7 relative to the average LAE spatial density (\bar{rho}) in the imaged field. Further, \bar{rho} is twice that derived by other field LAE surveys. Spectroscopy with Keck/DEIMOS yielded redshifts for 164 galaxies (79 LAEs and 85 LBGs); 65 lie at a redshift of 3.785+/-0.010. The velocity dispersion of galaxies near the core is {sigma}=350+/-40km/s, a value robust to selection effects. The overdensities are likely to collapse into systems with present-day masses of >10^15^M_{sun}_ and >6x10^14^M_{sun}_. The low velocity dispersion may suggest a dynamically young protocluster. We find a weak trend between narrow-band (Ly{alpha}) luminosity and environmental density: the Ly{alpha} luminosity is enhanced on average by 1.35x within the protocluster core. There is no evidence that the Ly{alpha} equivalent width depends on environment. These suggest that star formation and/or active galactic nucleus (AGN) activity is enhanced in the higher-density regions of the structure. PC 217.96+32.3 is a Coma cluster analog, witnessed in the process of formation.
- ID:
- ivo://CDS.VizieR/J/A+A/379/90
- Title:
- Candidate Planetary Nebulae in M81
- Short Name:
- J/A+A/379/90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File table1.dat contains the identification number, the coordinates (2000), the [OIII]5007 and the H{alpha}+[NII] flux of the candidate PNe detected in Messier 81, using the Isaac Newton Telescope (INT) (La Palma, Spain) in 2000, December and 2001, January. The accuracy on position is approximately 0.5 arcsec.
- ID:
- ivo://CDS.VizieR/J/A+A/367/498
- Title:
- Candidate Planetary Nebulae in M 33
- Short Name:
- J/A+A/367/498
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File table1.dat contains the identification number, the coordinates (2000), the H{alpha}+[NII] flux and the [OIII]5007 flux of the PNe detected in Messier 33, with the Isaac Newton Telescope (INT) (La Palma, Spain) in 1998, November. File table2.dat contains the identification number, the coordinates (2000), the H{alpha} flux, the [OIII]5007 flux and the continuum flux (at lambda 5550{AA} in Stroemgrem filter) of emission lines objects with non-negligible continuum emission detected in Messier 33, with the INT (La Palma, Spain) in 1998, November.
- ID:
- ivo://CDS.VizieR/J/ApJ/872/199
- Title:
- Candidate spectrophotometric standard DA WDs
- Short Name:
- J/ApJ/872/199
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present precise photometry and spectroscopy for 23 candidate spectrophotometric standard white dwarfs. The selected stars are distributed in the Northern hemisphere and around the celestial equator, and are all fainter than r~16.5mag. This network of stars, when established as standards and together with the three Hubble Space Telescope primary CALSPEC white dwarfs, will provide a set of spectrophotometric standards to directly calibrate data products to better than 1%. In future deep photometric surveys and facilities, these new faint standard white dwarfs will have enough signal-to-noise ratio to be measured accurately while still avoiding saturation. They will also fall within the dynamic range of large telescopes and their instruments for the foreseeable future. This paper discusses the provenance of the observational data for our candidate standard stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/735/41
- Title:
- Carbon and oxygen abundances in FGK stars
- Short Name:
- J/ApJ/735/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present carbon and oxygen abundances for 941 FGK stars -the largest such catalog to date. We find that planet-bearing systems are enriched in these elements. We self-consistently measure N_C_/N_O_, which is thought to play a key role in planet formation. We identify 46 stars with N_C_/N_O_>=1.00 as potential hosts of carbon-dominated exoplanets. We measure a downward trend in [O/Fe] versus [Fe/H] and find distinct trends in the thin and thick disks, supporting the work of Bensby et al. Finally, we measure sub-solar N_C_/N_O_=0.40^+0.11^_-0.07_, for WASP-12, a surprising result as this star is host to a transiting hot Jupiter whose dayside atmosphere was recently reported to have N_C_/N_O_>=1 by Madhusudhan et al. Our measurements are based on 15,000 high signal-to-noise spectra taken with the Keck 1 telescope as part of the California Planet Search. We derive abundances from the [OI] and CI absorption lines at {lambda}=6300 and 6587{AA} using the SME spectral synthesizer.
