- ID:
- ivo://CDS.VizieR/J/MNRAS/437/1070
- Title:
- DYNAMO. H{alpha} luminous galaxies sample
- Short Name:
- J/MNRAS/437/1070
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- DYNAMO is a multiwavelength, spatially resolved survey of local (z~0.1) star-forming galaxies designed to study evolution through comparison with samples at z=~2. Half of the sample has integrated H{alpha luminosities of >10^42^erg/s, the typical lower limit for resolved spectroscopy at z=~2. The sample covers a range in stellar mass (10^9^-10^11^M_{sun_) and star formation rate (0.2-100M_{sun}_/yr). In this first paper of a series, we present integral-field spectroscopy of H{alpha emission for the sample of 67 galaxies. We infer gas fractions in our sample as high as =~0.8, higher than typical for local galaxies. Gas fraction correlates with stellar mass in galaxies with star formation rates below 10M_{sun}_/yr, as found by COLDGASS, but galaxies with higher star formation rates have higher than expected gas fractions. There is only a weak correlation, if any, between gas fraction and gas velocity dispersion. Galaxies in the sample visually classified as disc-like are offset from the local stellar mass Tully-Fisher relation to higher circular velocities, but this offset vanishes when both gas and stars are included in the baryonic Tully-Fisher relation. The mean gas velocity dispersion of the sample is =~50km/s, and V/{sigma} ranges from 2 to 10 for most of the discs, similar to 'turbulent' galaxies at high redshift. Half of our sample show disc-like rotation, while ~20 percent show no signs of rotation. The division between rotating and non-rotating is approximately equal for the sub-samples with either star formation rates >10M_{sun}_/yr, or specific star formation rates typical of the star formation 'main sequence' at z=~2. Across our whole sample, we find good correlation between the dominance of `turbulence' in galaxy discs (as expressed by V/{sigma}) and gas fraction as has been predicted for marginally stable Toomre discs. Comparing our sample with many others at low- and high-redshift reveals a correlation between gas velocity dispersion and star formation rate. These findings suggest the DYNAMO discs are excellent candidates for local galaxies similar to turbulent z=~2 disc galaxies.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/578/A30
- Title:
- Emission-line galaxies in ZwCl0024.0+1652
- Short Name:
- J/A+A/578/A30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The cores of clusters at 0<~z<~1 are dominated by quiescent early-type galaxies, whereas the field is dominated by star-forming late-type galaxies. Clusters grow through the accretion of galaxies and groups from the surrounding field, which implies that galaxy properties, notably the star formation ability, are altered as they fall into overdense regions. The critical issues for understanding this evolution are how the truncation of star formation is connected to the morphological transformation and what physical mechanism is responsible for these changes. The GaLAxy Cluster Evolution Survey (GLACE) is conducting a thorough study of the variations in galaxy properties (star formation, AGN activity, and morphology) as a function of environment in a representative and well-studied sample of clusters. To address these questions, the GLACE survey is making a deep panoramic survey of emission line galaxies (ELG), mapping a set of optical lines ([OII], [OIII], H{beta} and H{alpha}/[NII] when possible) in several galaxy clusters at z~0.40, 0.63, and 0.86. Using the tunable filters (TF) of the OSIRIS instrument at the 10.4m GTC telescope, the GLACE survey applies the technique of TF tomography: for each line, a set of images are taken through the OSIRIS TF, each image tuned at a different wavelength (equally spaced), to cover a rest frame velocity range of several thousand km/s centred on the mean cluster redshift, and scanned for the full TF field of view of an 8arcmin diameter. Here we present the first results of the GLACE project, targeting the H{alpha}/[NII] lines in the intermediate-redshift cluster ZwCl0024.0+1652 at z=0.395. Two pointings have been performed that cover ~2*r_vir_.
- ID:
- ivo://CDS.VizieR/J/ApJ/706/553
- Title:
- Fluxes in nearby star-forming galaxies
- Short Name:
- J/ApJ/706/553
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Compared to starburst galaxies, normal star-forming galaxies have been shown to display a much larger dispersion of the dust attenuation at fixed reddening through studies of the IRX-{beta} diagram (the IR/UV ratio "IRX" versus the UV color "{beta}"). To investigate the causes of this larger dispersion and attempt to isolate second parameters, we have used GALEX UV, ground-based optical, and Spitzer infrared imaging of eight nearby galaxies, and examined the properties of individual UV and 24um selected star-forming regions. We concentrated on star-forming regions, in order to isolate simpler star formation histories than those that characterize whole galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/594/A120
- Title:
- Gaia-ESO Survey: Hydrogen lines in red giants
- Short Name:
- J/A+A/594/A120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Red giant stars are perhaps the most important type of stars for Galactic and extra-galactic archaeology: they are luminous, occur in all stellar populations, and their surface temperatures allow precise abundance determinations for many different chemical elements. Yet, the full star formation and enrichment history of a galaxy can be traced directly only if two key observables can be determined for large stellar samples: age and chemical composition. While spectroscopy is a powerful method to analyse the detailed abundances of stars, stellar ages are the missing link in the chain, since they are not a direct observable. However, spectroscopy should be able to estimate stellar masses, which for red giants directly infer ages provided their chemical composition is known. Here we establish a new empirical relation between the shape of the hydrogen line in the observed spectra of red giants and stellar mass determined from asteroseismology. The relation allows determining stellar masses and ages with an accuracy of 10-15%. The method can be used with confidence for stars in the following range of stellar parameters: 4000<T_eff_<5000K, 0.5<logg<3.5, -2.0<[Fe/H]<0.3, and luminosities logL/L_{sun}_<2.5. Our analysis provides observational evidence that the H_{alpha}_ spectral characteristics of red giant stars are tightly correlated with their mass and therefore their age. We also show that the method samples well all stellar populations with ages above 1Gyr. Targeting bright giants, the method allows obtaining simultaneous age and chemical abundance information far deeper than would be possible with asteroseismology, extending the possible survey volume to remote regions of the Milky Way and even to neighbouring galaxies such as Andromeda or the Magellanic Clouds even with current instrumentation, such as the VLT and Keck facilities.
- ID:
- ivo://CDS.VizieR/J/MNRAS/505/1135
- Title:
- Gaia/IPHAS catalogue of Ha-excess sources
- Short Name:
- J/MNRAS/505/1135
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present a catalogue of point-like H{alpha}-excess sources in the Northern Galactic Plane. Our catalogue is created using a new technique that leverages astrometric and photometric information from Gaia to select H{alpha}-bright outliers in the INT Photometric H{alpha} Survey of the Northern Galactic Plane (IPHAS), across the colour-absolute magnitude diagram. To mitigate the selection biases due to stellar population mixing and to extinction, the investigated objects are first partitioned with respect to their positions in the Gaia colour-absolute magnitude space, and in the Galactic coordinates space, respectively. The selection is then performed on both partition types independently. Two significance parameters are assigned to each target, one for each partition type. These represent a quantitative degree of confidence that the given source is a reliable H{alpha}-excess candidate, with reference to the other objects in the corresponding partition. Our catalogue provides two flags for each source, both indicating the significance level of the H{alpha}-excess. By analysing their intensity in the H{alpha} narrow band, 28496 objects out of 7474835 are identified as H{alpha}-excess candidates with a significance higher than 3. The completeness fraction of the H{alpha} outliers selection is between 3% and 5%. The suggested 5sigma conservative cut yields a purity fraction of 81.9%.
- ID:
- ivo://CDS.VizieR/IV/36
- Title:
- Gaia-IPHAS/KIS Value-Added Catalogues
- Short Name:
- IV/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sub-arcsecond cross-match of Gaia DR2 (Cat. I/345) against the INT Photometric H-alpha Survey of the Northern Galactic Plane Data Release 2 (IPHAS DR2, Cat. II/321) and the Kepler-INT Survey (KIS, Cat. J/AJ/144/24). The resulting value-added catalogues (VACs) provide additional precise photometry to the Gaia photometry (r, i and H-alpha for IPHAS, with additional U and g for KIS). In building the catalogue, proper motions given in Gaia DR2 are wound back to match the epochs of IPHAS DR2, thus ensuring high proper motion objects are appropriately cross-matched. The catalogues contain 7927224 and 791071 sources for IPHAS and KIS, respectively. The requirement of >5 sigma parallax detection for every included source means that distances out to 1-1.5kpc are well covered. We define two additional parameters for each catalogued object: (i) fc, a magnitude-dependent tracer of the quality of the Gaia astrometric fit; (ii) fFP, the false-positive rate for parallax measurements determined from astrometric fits of a given quality at a given magnitude. Selection cuts based on these parameters can be used to clean colour-magnitude and colour-colour diagrams in a controlled and justified manner. We provide both full and light versions of the VAC, with VAC-light containing only objects that represent our recommended trade-off between purity and completeness. Uses of the catalogues include the identification of new variable stars in the matched data sets, and more complete identification of H-alpha-excess emission objects thanks to separation of high-luminosity stars from the main sequence.
- ID:
- ivo://CDS.VizieR/J/ApJ/833/178
- Title:
- GLASS. VII. H{alpha} maps
- Short Name:
- J/ApJ/833/178
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Exploiting the slitless spectroscopy taken as part of the Grism Lens-Amplified Survey from Space (GLASS), we present an extended analysis of the spatial distribution of star formation in 76 galaxies in 10 clusters at 0.3<z<0.7. We use 85 foreground and background galaxies in the same redshift range as a field sample. The samples are well matched in stellar mass (10^8^-10^11^M_{sun}_) and star formation rate (0.5-50M_{sun}_/yr). We visually classify galaxies in terms of broad band morphology, H{alpha} morphology, and likely physical process acting on the galaxy. Most H{alpha} emitters have a spiral morphology (41%+/-8% in clusters, 51%+/-8% in the field), followed by mergers/interactions (28%+/-8%, 31%+/-7%, respectively) and early-type galaxies (remarkably as high as 29%+/-8% in clusters and 15%+/-6% in the field). A diversity of H{alpha} morphologies is detected, suggesting a diversity of physical processes. In clusters, 30%+/-8% of the galaxies present a regular morphology, mostly consistent with star formation diffused uniformly across the stellar population (mostly in the disk component, when present). The second most common morphology (28%+/-8%) is asymmetric/jellyfish, consistent with ram-pressure stripping or other non-gravitational processes in 18%+/-8% of the cases. Ram-pressure stripping appears significantly less prominent in the field (2%+/-2%), where the most common morphology/mechanism appears to be consistent with minor gas-rich mergers or clump accretion. This work demonstrates that while environment-specific mechanisms affect galaxy evolution at this redshift, they are diverse and their effects are subtle. A full understanding of this complexity requires larger samples and detailed and spatially resolved physical models.
- ID:
- ivo://CDS.VizieR/J/A+A/608/A48
- Title:
- HAE229 CO (1-0) ATCA datacube
- Short Name:
- J/A+A/608/A48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is not yet known if the properties of molecular gas in distant protocluster galaxies are significantly acted by their environment as galaxies are in local clusters. Through a deep, 64 hours of effective on-source integration with the Australian Telescope Compact Array (ATCA), we discovered a massive, M_mol_=2.0+/-0.2x0^11^M_{sun}_, extended, ~40kpc, CO(1-0)-emitting disk in the protocluster surrounding the radio galaxy, MRC1138-262. The galaxy, at z_CO_=2.1478, is a clumpy, massive disk galaxy, M*~5x10^11^M_{sun}_, which lies 250kpc in projection from MRC1138-262 and is a known H{alpha} emitter, named HAE229. This source has a molecular gas fraction of ~30%. The CO emission has a kinematic gradient along its major axis, centered on the highest surface brightness rest-frame optical emission, consistent with HAE229 being a rotating disk. Surprisingly, a significant fraction of the CO emission lies outside of the UV/optical emission. In spite of this, HAE229 follows the same relation between star-formation rate and molecular gas mass as normal field galaxies. HAE229 is the first CO(1-0) detection of an ordinary, star-forming galaxy in a protocluster.We compare a sample of cluster members at z>0.4 that are detected in low-order CO transitions, with a similar sample of sources drawn from the field.We confirm findings that the CO-luminosity and full-width at half maximum (FWHM) are correlated in starbursts and show that this relation is valid for normal high-z galaxies as well as for those in overdensities. We do not find a clear dichotomy in the integrated Schmidt-Kennicutt relation for protocluster and field galaxies. Our results suggest that environment does not have an impact on the "star-formation electronic efficiency" or the molecular gas content of high-redshift galaxies. Not finding any environmental dependence in these characteristics, especially for such an extended CO disk, suggests that environmentally-specific processes such as ram pressure stripping do not operate electronic efficiently in (proto)clusters.
- ID:
- ivo://CDS.VizieR/J/MNRAS/506/3079
- Title:
- Halpha and other SFR indicators
- Short Name:
- J/MNRAS/506/3079
- Date:
- 18 Jan 2022 13:46:29
- Publisher:
- CDS
- Description:
- We present new H{alpha} photometry for the Star Formation Reference Survey (SFRS), a representative sample of star-forming galaxies in the local Universe. Combining these data with the panchromatic coverage of the SFRS, we provide calibrations of H{alpha}-based star-formation rates (SFRs) with and without correction for the contribution of [NII] emission. We consider the effect of extinction corrections based on the Balmer decrement, infrared excess, and spectral energy distribution (SED) fits. We compare the SFR estimates derived from SED fits, polycyclic aromatic hydrocarbons, hybrid indicators such as 24um+H{alpha}, 8um+H{alpha}, FIR+FUV, and H{alpha} emission for a sample of purely star-forming galaxies. We provide a new calibration for 1.4GHz-based SFRs by comparing to the H{alpha} emission, and we measure a dependence of the radio-to-H{alpha} emission ratio based on galaxy stellar mass. Active galactic nuclei introduce biases in the calibrations of different SFR indicators but have only a minimal effect on the inferred SFR densities from galaxy surveys. Finally, we quantify the correlation between galaxy metallicity and extinction.
- ID:
- ivo://CDS.VizieR/J/ApJ/744/44
- Title:
- H{alpha} and UV fluxes in nearby galaxies
- Short Name:
- J/ApJ/744/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We consider the effects of non-constant star formation histories (SFHs) on H{alpha} and GALEX far-ultraviolet (FUV) star formation rate (SFR) indicators. Under the assumption of a fully populated Chabrier initial mass function (IMF), we compare the distribution of H{alpha}-to-FUV flux ratios from ~1500 simple, periodic model SFHs with observations of 185 galaxies from the Spitzer Local Volume Legacy survey. We find a set of SFH models that are well matched to the data, such that more massive galaxies are best characterized by nearly constant SFHs, while low-mass systems experience burst amplitudes of ~30 (i.e., an increase in the SFR by a factor of 30 over the SFR during the inter-burst period), burst durations of tens of Myr, and periods of ~250 Myr; these SFHs are broadly consistent with the increased stochastic star formation expected in systems with lower SFRs. We analyze the predicted temporal evolution of galaxy stellar mass, R-band surface brightness, H{alpha}-derived SFR, and blue luminosity, and find that they provide a reasonable match to observed flux distributions. We find that our model SFHs are generally able to reproduce both the observed systematic decline and increased scatter in H{alpha}-to-FUV ratios toward low-mass systems, without invoking other physical mechanisms.
