- 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.
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Search Results
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJ/706/599
- Title:
- H{alpha} and UV SFR in the local volume
- Short Name:
- J/ApJ/706/599
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a complete sample of ~300 star-forming galaxies within 11Mpc of the Milky Way, we evaluate the consistency between star formation rates (SFRs) inferred from the far ultraviolet (FUV) non-ionizing continuum and H{alpha} nebular emission, assuming standard conversion recipes in which the SFR scales linearly with luminosity at a given wavelength. Our analysis probes SFRs over 5 orders of magnitude, down to ultra-low activities on the order of ~10^-4^M_{sun}_/yr. The data are drawn from the 11Mpc H{alpha} and Ultraviolet Galaxy Survey (11HUGS), which has obtained H{alpha} fluxes from ground-based narrowband imaging, and UV fluxes from imaging with GALEX.
- ID:
- ivo://CDS.VizieR/J/A+AS/137/495
- Title:
- Halpha Catalogue of HCG Galaxies
- Short Name:
- J/A+AS/137/495
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present H{alpha} photometry for a sample of 95 galaxies in Hickson Compact Groups (Cat. <VII/213>) obtained from observations of 31 groups. The Catalogue lists isophotal and adaptive aperture (Kron aperture) flux measurements for about 75% of the accordant galaxies inside the observed HCGs, 22 out of which are upper limits. Non standard data reduction procedures have been used to obtain the continuum subtracted H{alpha} images for each HCG of the target sample. Flux calibration has also been performed in order to obtain H{alpha} luminosities for the whole sample. Both the data reduction and calibration procedures are carefully described in the paper.
- ID:
- ivo://CDS.VizieR/J/A+A/629/A102
- Title:
- Halpha data cube of Stephan's Quintet
- Short Name:
- J/A+A/629/A102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stephan's Quintet (SQ), the prototypical compact group of galaxies in the local Universe, has been observed with the imaging Fourier transform spectrometer SITELLE, attached to the Canada-France-Hawaii- Telescope, to perform a deep search for intergalactic star-forming emission. In this paper we present the extended ionised gaseous structures detected and analyse their kinematical properties. The large field of view (11'x11') and the spectral ranges of SITELLE have allowed a thorough study of the entire galaxy system, its interaction history and the main properties of the ionised gas. The observations have revealed complex three-dimensional strands in SQ seen for the first time, as well as the spatially resolved velocity field for a new SQ dwarf galaxy (M82-like) and the detailed spectral map of NGC7320c, confirming its AGN nature. A total of 175 SQ Halpha emission regions have been found, 22 of which present line profiles with at least two kinematical components. We studied 12 zones and 28 sub-zones in the SQ system in order to define plausible physical spatial connections between its different parts in the light of the kinematical information gathered. In this respect we have found five velocity systems in SQ: i) v=[5600-5900]km/s associated with the new intruder and the southern debris region; ii) v=[5900-6100]km/s, associated with the north starburst A and south starburst A and the strands connected to these zones; iii) v=[6100-6600]km/s, associated with the strands from the large-scale shock region (LSSR); iv) v=[6600-6800]km/s, associated with the young tidal tail, the starburst A (SQA), NGC7319, and the NGC7319 north lobe; and v) v=[6800-7000]km/s, associated with the strands seen connecting LSSR with SQA. We fail to detect ionised gas emission in the old tail, neither in the vicinity of NGC7318A nor in NGC7317, and the connection between NGC7319 north lobe and SQA cannot be confirmed. Conversely, a clear gaseous bridge has been confirmed both spatially and kinematically between the LSSR zone and the NGC7319 AGN nucleus. Finally, a larger scale, outer rim winding the NGC7318B/A system clockwise north-west to south-east has been highlighted in continuum and in H{alpha}. This structure may be reminiscent of a sequence of a previously proposed scenario for SQ a sequence of individual interactions.
- ID:
- ivo://CDS.VizieR/J/AJ/134/2474
- Title:
- H{alpha} emission-line stars in 7 dwarfs galaxies
- Short Name:
- J/AJ/134/2474
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a search for H{alpha} emission-line stars in M31, M33, and seven dwarfs in or near the Local Group (IC 10, NGC 6822, WLM, Sextans B, Sextans A, Pegasus, and the Phoenix dwarf) using interference filter imaging with the KPNO and CTIO 4m telescopes and Mosaic cameras. The survey is aimed primarily at identifying new luminous blue variables (LBVs) from their spectroscopic similarity to known LBVs, avoiding the bias toward photometric variability, which may require centuries to manifest itself if LBVs go through long quiescent periods. Follow-up spectroscopy with WIYN confirms that our survey detected a wealth of stars whose spectra are similar to the known LBVs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/473/1977
- Title:
- H-alpha emitters in/towards USS 1558
- Short Name:
- J/MNRAS/473/1977
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried out deep H{alpha} narrowband imaging with 10h net integrations towards the young protocluster, USS1558-003 at z=2.53 with the Subaru Telescope. This system is composed of four dense groups with massive local overdensities, traced by 107 H{alpha} emitters (HAEs) with stellar masses and dust-corrected star formation rates down to 1x10^8^M_{sun}_ and 3M_{sun}_/yr, respectively. We have investigated the environmental dependence of various physical properties within the protocluster by comparing distributions of HAEs in higher and lower densities with a standard Kolmogorov-Smirnov test. At 97 per cent confidence level, we find enhanced star formation across the star-forming main sequence of HAEs living in the most extreme 'supergroup', corresponding to the top quartile of overdensities. Furthermore, we derive distribution functions of H{alpha} luminosity and stellar mass in group and intergroup regions, approximately corresponding to 30 and 8 times higher densities than the general field. As a consequence, we identify 0.7 and 0.9dex higher cut-offs in H{alpha} luminosity and stellar mass functions in the dense groups, respectively. On the other hand, HAEs in the intergroup environment of the protocluster show similar distribution functions to those of field galaxies despite residing in significant overdensities. In the early phase of cluster formation, as inferred from our results, the densest parts in the protocluster have had an accelerated formation of massive galaxies. We expect that these eventually grow and transform into early-type galaxies at the bright end of the red sequence as seen in present-day rich clusters of galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJS/175/128
- Title:
- H{alpha} emitting galaxies in COSMOS-2 field
- Short Name:
- J/ApJS/175/128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To derive a new H{alpha} luminosity function and to understand the clustering properties of star-forming galaxies at z~0.24, we have made a narrowband imaging survey for H{alpha}-emitting galaxies in the Hubble Space Telescope (HST) COSMOS 2 square degree field. We used the narrowband filter NB816 ({lambda}_c_=8150{AA}, {Delta}{lambda}=120{AA}) and sampled H{alpha} emitters with EW_obs_(H{alpha}+[NII])>12{AA} in a redshift range between z=0.233 and 0.251 corresponding to a depth of 70Mpc. We obtained 980 H{alpha}-emitting galaxies in a sky area of 5540arcmin^2^, corresponding to a survey volume of 3.1x10^4^Mpc^3^.
- ID:
- ivo://CDS.VizieR/J/ApJ/549/820
- Title:
- H{alpha} flux of ACCG 114 galaxies
- Short Name:
- J/ApJ/549/820
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a wide-field survey for H{alpha}-emitting galaxies in the cluster AC 114 at z=0.32. Spectra centered on H{alpha} at the cluster redshift have been obtained for 586 galaxies to I_tot_~22 out to a radius of ~h_50_^-1^Mpc. At most, only ~10% of these were found to be H{alpha}-emitting cluster members. These objects are predominantly blue and of late-type spiral morphology, consistent with them hosting star formation. However, ~65% of the cluster members classified morphologically as spirals (with HST) have no detectable H{alpha} emission; star formation and morphological evolution in cluster galaxies appear to be largely decoupled. Changes in the H{alpha} detection rate and the strength of H{alpha} emission with environment (as traced by local galaxy density) are found to be weak within the region studied. Star formation within the cluster members is also found to be strongly and uniformly suppressed with the rates inferred from the H{alpha} emission not exceeding 4M_{sun}_/yr, and AC 114's H{alpha} luminosity function being an order of magnitude below that observed for field galaxies at the same redshift. None of the galaxies detected have the high star formation rates associated with "starburst" galaxies; however, this may still be reconcilable with the known (8%+/-3%) fraction of "post-starburst" galaxies within AC 114, given the poorly determined but short lifetimes of starbursts and the possibility that much of the associated star formation is obscured by dust.
- ID:
- ivo://CDS.VizieR/J/ApJ/677/169
- Title:
- H{alpha} galaxies at z=0.84
- Short Name:
- J/ApJ/677/169
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an H{alpha} near-infrared narrowband survey searching for star-forming galaxies at redshift z=0.84. This work is an extension of our previous narrowband studies in the optical at lower redshifts. After removal of stars and redshift interlopers (using spectroscopic and photometric redshifts), we build a complete sample of 165 H{alpha} emitters in the extended Groth strip and GOODS-N fields with L(H{alpha})>10^41^ergs/s. We compute the H{alpha} luminosity function at z=0.84 after corrections for [NII] flux contamination, extinction, systematic errors, and incompleteness. Our sources present an average dust extinction of A(H{alpha})=1.5mag. Adopting H{alpha} as a surrogate for the instantaneous SFR, we measure an extinction-corrected SFR density of 0.17^+0.03^_-0.03_M_{sun}_/yr/Mpc^3^. Combining this result to our prior measurements at z=0.02, 0.24, and 0.40, we derive an H{alpha}-based evolution of the SFR density proportional to (1+z)^{beta}^ with {beta}=3.8+/-0.5. This evolution is consistent with that derived by other authors using different SFR tracers.