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- ID:
- ivo://CDS.VizieR/J/A+A/568/L8
- Title:
- VUDS extreme emission line 0.2<~z<~0.9 galaxies
- Short Name:
- J/A+A/568/L8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 31 low-luminosity (-14.5>~M_AB_(B)>~-18.8), extreme emission line galaxies (EELGs) at 0.2<~z<~0.9 identified by their unusually high rest-frame equivalent widths (100<=EW[OIII]<=1700{AA}) as part of the VIMOS Ultra Deep Survey (VUDS). VIMOS optical spectra of unprecedented sensitivity (I_AB_~25mag) along with multiwavelength photometry and HST imaging are used to investigate spectrophotometric properties of this unique sample and to explore, for the first time, the very low stellar mass end (M_*_<~10^8^M_{sun}_) of the luminosity-metallicity (LZR) and mass-metallicity (MZR) relations at z<1. Characterized by their extreme compactness (R_50_<1kpc), low stellar mass and enhanced specific star formation rates (sSFR=SFR/M_*_~10^-9^-10^-7^yr^-1^), the VUDS EELGs are blue dwarf galaxies likely experiencing the first stages of a vigorous galaxy-wide starburst. Using Te-sensitive direct and strong-line methods, we find that VUDS EELGs are low-metallicity (7.5<~12+log(O/H)<~8.3) galaxies with high ionization conditions (log(q_ion_)>~8cm/s), including at least three EELGs showing HeII{lambda}4686{AA} emission and four extremely metal-poor (<~10% solar) galaxies. The LZR and MZR followed by VUDS EELGs show relatively large scatter, being broadly consistent with the extrapolation toward low luminosity and mass from previous studies at similar redshift. However, we find evidence that galaxies with younger and more vigorous star formation --as characterized by their larger EWs, ionization and sSFR-- tend to be more metal poor at a given stellar mass.
- ID:
- ivo://CDS.VizieR/J/A+A/634/A97
- Title:
- VUDS UV and Ly{alpha} luminosity functions
- Short Name:
- J/A+A/634/A97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The star formation rate density (SFRD) evolution presents an area of great interest in the studies of galaxy evolution and reionization. The current constraints of SFRD at z>5 are based on the rest-frame UV luminosity functions with the data from photometric surveys. The VIMOS UltraDeep Survey (VUDS) was designed to observe galaxies at redshifts up to ~6 and opened a window for measuring SFRD at z>5 from a spectroscopic sample with a well-controlled selection function. We establish a robust statistical description of the star-forming galaxy population at the end of cosmic HI reionization (5.0<=z<=6.6) from a large sample of 49 galaxies with spectroscopically confirmed redshifts. We determine the rest-frame UV and Ly{alpha} luminosity functions and use them to calculate SFRD at the median redshift of our sample z=5.6. We selected a sample of galaxies at 5.0<=z_spec_<=6.6 from the VUDS. We cleaned our sample from low redshift interlopers using ancillary photometric data. We identified galaxies with Ly{alpha} either in absorption or in emission, at variance with most spectroscopic samples in the literature where Ly{alpha} emitters (LAE) dominate. We determined luminosity functions using the 1/V_max_ method. The galaxies in this redshift range exhibit a large range in their properties. A fraction of our sample shows strong Ly{alpha} emission, while another fraction shows Ly{alpha} in absorption. UV-continuum slopes vary with luminosity, with a large dispersion. We find that star-forming galaxies at these redshifts are distributed along the main sequence in the stellar mass vs. SFR plane, described with a slope {alpha}=0.85+/-0.05. We report a flat evolution of the specific SFR compared to lower redshift measurements. We find that the UV luminosity function is best reproduced by a double power law, while a fit with a Schechter function is only marginally inferior. The Ly{alpha} luminosity function is best fitted with a Schechter function. We derive a logSFRD_UV_(M_{sun}_/yr/Mpc^3^)=-1.45^+0.06^_-0.08_ and logSFRD_Ly{alpha}_(M_{sun}_/yr/Mpc^3^)=-1.40^+0.07^_-0.08_. The SFRD derived from the Ly{alpha} luminosity function is in excellent agreement with the UV-derived SFRD after correcting for IGM absorption.Conclusions. Our new SFRD measurements at a mean redshift of z=5.6 are ~0.2dex above the mean SFRD reported in Madau & Dickinson (2014ARA&A..52..415M), but in excellent agreement with results from Bouwens et al. (2015ApJ...803...34B). These measurements confirm the steep decline of the SFRD at z>2. The bright end of the Ly{alpha} luminosity function has a high number density, indicating a significant star formation activity concentrated in the brightest LAE at these redshifts. LAE with equivalent width EW>25{AA} contribute to about 75% of the total UV-derived SFRD. While our analysis favors low dust content in 5.0<z<6.6, uncertainties on the dust extinction correction and associated degeneracy in spectral fitting will remain an issue, when estimating the total SFRD until future surveys extending spectroscopy to the NIR rest-frame spectral domain, such as with JWST.
- ID:
- ivo://CDS.VizieR/J/ApJS/150/1
- Title:
- VV29 and NGC 4676 HST photometry
- Short Name:
- J/ApJS/150/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of the faint galaxy population in the Advanced Camera for Surveys (ACS) Early Release Observation fields VV 29 (UGC 10214) and NGC 4676. These observations cover a total area of 26.3arcmin^2^ and have depths close to that of the Hubble Deep Fields in the deepest part of the VV 29 image, with 10{sigma} detection limits for point sources of 27.8, 27.6, and 27.2 AB magnitudes in the g_F475W_, V_F606W_, and I_F814W_ bands, respectively.
4155. VVDS14h redshift catalog
- ID:
- ivo://CDS.VizieR/J/MNRAS/473/1879
- Title:
- VVDS14h redshift catalog
- Short Name:
- J/MNRAS/473/1879
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use observations made with the Giant Metrewave Radio Telescope (GMRT) to probe the neutral hydrogen (HI) gas content of field galaxies in the VIMOS VLT Deep Survey (VVDS) 14h field at z~=0.32. Because the HI emission from individual galaxies is too faint to detect at this redshift, we use an HI spectral stacking technique using the known optical positions and redshifts of the 165 galaxies in our sample to co-add their HI spectra and thus obtain the average HI mass of the galaxies. Stacked HI measurements of 165 galaxies show that >~95 per cent of the neutral gas is found in blue, star-forming galaxies. Among these galaxies, those having lower stellar mass are more gas rich than more massive ones. We apply a volume correction to our HI measurement to evaluate the HI gas density at z~=0.32 as {OMETA}_HI_=(0.50+/-0.18)x10^-3^ in units of the cosmic critical density. This value is in good agreement with previous results at z<0.4, suggesting no evolution in the neutral hydrogen gas density over the last ~4Gyr. However the z~=0.32 gas density is lower than that at z~5 by at least a factor of two.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A146
- Title:
- VVV galaxies behind Galactic bulge overdensity
- Short Name:
- J/A+A/646/A146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The extragalactic vision we have through the Milky Way is very unclear. There is significant extinction of the optical emission from objects located in the region called the Zone of Avoidance (ZOA). NIR wavelengths are less affected by extinction, and therefore the infrared surveys in this zone are a potential source of astronomical discoveries. Nevertheless, these observations need to be compared with cosmological simulations in order to carry out high-accuracy studies. Our aim is to identify extragalactic sources in the ZOA, using infrared images of the VVV survey. We consider mock galaxy catalogues in order to interpret observational results. We studied a region of 1.636 square degrees corresponding to the VVV tile b204. Using SExtractor, we analysed photometric data generating a catalogue of extended sources in this area. In order to confirm these sources as galaxy candidates we visually inspected RGB images looking for typical galaxy features. Using 2MASX and GCMW catalogued sources we tested completeness and contamination of our catalogue and define suitable colour cuts to select galaxies. We also compared the observational results with those obtained from two semi-analytical models on Dark Matter simulations. One galaxy catalogue was constructed with the SAG semi-analytic model of galaxy formation, and the other one was constructed with the L-Galaxies semi-analytic model. By adopting CLASS_STAR<0.5, r1/2>0.7 arcsec and specific colour cuts (J-Ks>0.97, J-H>0 and H-Ks>0) we generated an automatic catalogue of extended sources. After visual inspection we identified 624 sources with 10<Ks<17 as galaxy candidates.The contamination of the automatic catalogue is 28% when considering visually confirmed galaxies as reliable objects. The estimated completeness is 87% up to magnitude Ks=13.5. We analysed the spatial distribution of galaxy candidates, finding a high concentration of galaxies in a small region of 15 arcmin radius. This region has three times higher density than similar areas in the tile. We compared the number of galaxies in this small area with the mean density values obtained from a suitable sample of galaxies from semi-analytic models finding that our results are consistent with an overdensity region. Using VVV near-infrared data and mock catalogues we detect new extragalactic sources that have not been identified by other catalogues. We demonstrate the potentiality of the VVV survey in finding and studying a large number of galaxy candidates and extragalactic structures obscured by the Milky Way.
4157. Warm IRAS sources. II.
- ID:
- ivo://CDS.VizieR/J/A+AS/96/389
- Title:
- Warm IRAS sources. II.
- Short Name:
- J/A+AS/96/389
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical spectra for a sample of 563 high-latitude IRAS sources selected from the Point Source Catalog to have relatively warm 25 to 60 micron colours. We have shown this selection criterion to be an efficient indicator for finding Seyfert galaxies. Plots of the optical spectra are shown and the fluxes of the strongest emission lines in these spectra are tabulated. After excluding 128 sources which are clearly galactic foreground objects, we obtained spectroscopic information for 358 extragalactic objects. Emission-line ratios have been used to classify these objects, resulting in 80 Seyfert 1, 141 Seyfert 2 and 133 HII-type objects. In comparison with samples of active nuclei selected in other ways, about 50% of known Seyfert nuclei are included by our colour criteria. This fraction is larger for high luminosities, reaching 80% for quasar luminosities. For lower-luminosity objects, contamination by the host galaxies becomes important and the sample becomes seriously incomplete. It should be moderately complete and representative for core luminosities greater than 10^23.5^W/Hz at 12m. Finally, the infrared luminosity function for each type of object is derived; the shapes for Seyfert 1 and 2 nuclei are identical, with a type 2/type 1 space-density ratio of 3.0. Our census is consistent with an obscuration scheme for producing both types of object from a single parent population, though the origin of excess cool IR radiation Irom many Seyferts is still unclear. We note the appearance of an apparent type II supernova in IRAS 0225-103 observed in 1985 September. Its spectrum suggests that it was observed between 1 and 2 months after maximum, perhaps in a "plateau" phase.
4158. Warm IRAS sources. IV.
- ID:
- ivo://CDS.VizieR/J/A+AS/108/61
- Title:
- Warm IRAS sources. IV.
- Short Name:
- J/A+AS/108/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a list of objects observed to have extended line emission in our spectroscopic survey of infrared-warm AGN. Slit spectroscopic data were obtained for 225 galaxies identified with objects in our compendium of warm sources from the IRAS Point Source Catalog. Of these, 44 have spatially-resolved emission-line regions along the (arbitrarily placed) slit direction. Measured (projected) linear sizes of the ionized gas regions extend to >10kpc. In the case of the IRAS Seyfert galaxies the spatially extended line emission appears to have a lower ionization state than the nuclear emission. This contrasts with the warm IRAS starbust galaxies for which there is no significant difference between the ionization states of the nuclear and extended emission. For the starburst galaxies, there is a relation between the extent of star formation as seen at H{alpha} and the far-IR colors, with more compact bursts having "warmer" colors.
- ID:
- ivo://CDS.VizieR/J/A+A/588/A131
- Title:
- Warm ISM in the Sagittarius A Complex
- Short Name:
- J/A+A/588/A131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the spatial and spectral distribution of the local standard of rest (LSR) velocity resolved submillimetre emission from the warm (25-90K) gas in the Sgr A Complex, located in the Galactic centre. We present large-scale submillimetre heterodyne observations towards the Sgr A Complex covering ~300-arcmin2. These data were obtained in the frame of the Herschel EXtraGALactic guaranteed time key program (HEXGAL) with the Herschel-HIFI satellite and are complemented with submillimetre observations obtained with the NANTEN2/SMART telescope as part of the NANTEN2/SMART Central Nuclear Zone Survey. The observed species are CO(J=4-3) at 461.0GHz observed with the NANTEN2/SMART telescope, and [CI] 3P1-3P0 at 492.2GHz, [CI] 3P2-3P1 at 809.3GHz, [NII] 3P1-3P0 at 1461.1GHz, and [CII] 2P3/2-2P1/2 at 1900.5GHz observed with the Herschel-HIFI satellite. The observations are presented in a 1km/s spectral resolution and a spatial resolution ranging from 46-arcsec to 28-arcsec. The spectral coverage of the three lower frequency lines is +/-200km/s, while in the two high frequency lines, the upper LSR velocity limit is +94km/s and +145km/s for the [NII] and [CII] lines, respectively. The spatial distribution of the emission in all lines is very widespread. The bulk of the carbon monoxide emission is found towards Galactic latitudes below the Galactic plane, and all the known molecular clouds are identified. Both neutral atomic carbon lines have their brightest emission associated with the +50km/s cloud. Their spatial distribution at this LSR velocity describes a crescent-shape structure, which is probably the result of interaction with the energetic event (one or several supernovae explosions) that gave origin to the non-thermal Sgr A-East source. The [CII] and [NII] emissions have most of their flux associated with the thermal arched-filaments and the H region and bright spots in [CII] emission towards the central nuclear disk (CND) are detected. Warm Gas at very high (|Vlsr|>100km/s) LSR velocities is also detected towards the line of sight to the Sgr A Complex, and it is most probably located outside the region, in the X1 orbits.
- ID:
- ivo://CDS.VizieR/J/AJ/156/295
- Title:
- Warm molecular hydrogen in nearby LIRGs
- Short Name:
- J/AJ/156/295
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Mid-infrared molecular hydrogen (H_2_) emission is a powerful cooling agent in galaxy mergers and in radio galaxies; it is a potential key tracer of gas evolution and energy dissipation associated with mergers, star formation, and accretion onto supermassive black holes. We detect mid-IR H_2_ line emission in at least one rotational transition in 91% of the 214 Luminous Infrared Galaxies (LIRGs) observed with Spitzer as part of the Great Observatories All-sky LIRG Survey. We use H_2_ excitation diagrams to estimate the range of masses and temperatures of warm molecular gas in these galaxies. We find that LIRGs in which the IR emission originates mostly from the Active Galactic Nuclei (AGN) have about 100 K higher H_2_ mass-averaged excitation temperatures than LIRGs in which the IR emission originates mostly from star formation. Between 10% and 15% of LIRGs have H_2_ emission lines that are sufficiently broad to be resolved or partially resolved by the high-resolution modules of Spitzer's Infrared Spectrograph (IRS). Those sources tend to be mergers and contain AGN. This suggests that a significant fraction of the H_2_ line emission is powered by AGN activity through X-rays, cosmic rays, and turbulence. We find a statistically significant correlation between the kinetic energy in the H_2_ gas and the H_2_ to IR luminosity ratio. The sources with the largest warm gas kinetic energies are mergers. We speculate that mergers increase the production of bulk inflows leading to observable broad H_2_ profiles and possibly denser gas.
