We present the Galaxy And Mass Assembly (GAMA) Panchromatic Data Release (PDR) constituting over 230 deg2 of imaging with photometry in 21 bands extending from the far-UV to the far-IR. These data ...complement our spectroscopic campaign of over 300k galaxies, and are compiled from observations with a variety of facilities including: GALaxy Evolution eXplorer, Sloan Digital Sky Survey, Visible and Infrared Telescope for Astronomy (VISTA), Wide-field Infrared Survey Explorer, and Herschel, with the GAMA regions currently being surveyed by VLT Survey Telescope (VST) and scheduled for observations by Australian Square Kilometer Array Pathfinder (ASKAP). These data are processed to a common astrometric solution, from which photometry is derived for ∼221 373 galaxies with r < 19.8 mag. Online tools are provided to access and download data cutouts, or the full mosaics of the GAMA regions in each band. We focus, in particular, on the reduction and analysis of the VISTA VIsta Kilo-degree INfrared Galaxy data, and compare to earlier data sets (i.e. 2MASS and UKIDSS) before combining the data and examining its integrity. Having derived the 21-band photometric catalogue, we proceed to fit the data using the energy balance code magphys. These measurements are then used to obtain the first fully empirical measurement of the 0.1–500 μm energy output of the Universe. Exploring the cosmic spectral energy distribution across three time-intervals (0.3–1.1, 1.1–1.8, and 1.8–2.4 Gyr), we find that the Universe is currently generating (1.5 ± 0.3) × 1035 h
70 W Mpc−3, down from (2.5 ± 0.2) × 1035 h
70 W Mpc−3 2.3 Gyr ago. More importantly, we identify significant and smooth evolution in the integrated photon escape fraction at all wavelengths, with the UV escape fraction increasing from 27(18) per cent at z = 0.18 in NUV(FUV) to 34(23) per cent at z = 0.06. The GAMA PDR can be found at: http://gama-psi.icrar.org/.
Abstract
We present the first major release of data from the SAMI Galaxy Survey. This data release focuses on the emission-line physics of galaxies. Data Release One includes data for 772 galaxies, ...about 20 per cent of the full survey. Galaxies included have the redshift range 0.004 < z < 0.092, a large mass range (7.6 < log M*/ M⊙ < 11.6), and star formation rates of ∼10−4 to ∼101M⊙ yr−1. For each galaxy, we include two spectral cubes and a set of spatially resolved 2D maps: single- and multi-component emission-line fits (with dust-extinction corrections for strong lines), local dust extinction, and star formation rate. Calibration of the fibre throughputs, fluxes, and differential atmospheric refraction has been improved over the Early Data Release. The data have average spatial resolution of 2.16 arcsec (full width at half-maximum) over the 15 arcsec diameter field of view and spectral (kinematic) resolution of R = 4263 (σ = 30 km s−1) around H α. The relative flux calibration is better than 5 per cent, and absolute flux calibration has an rms of 10 per cent. The data are presented online through the Australian Astronomical Observatory's Data Central.
Astronomy is rapidly approaching an impasse: very large datasets require remote or cloud-based parallel processing, yet many astronomers still try to download the data and develop serial code ...locally. Astronomers understand the need for change, but the hurdles remain high. We are developing a data archive designed from the ground up to simplify and encourage cloud-based parallel processing. While the volume of data we host remains modest by some standards, it is still large enough that download and processing times are measured in days and even weeks. We plan to implement a python based, notebook-like interface that automatically parallelises execution. Our goal is to provide an interface sufficiently familiar and user-friendly that it encourages the astronomer to run their analysis on our system in the cloud—astroinformatics as a service. We describe how our system addresses the approaching impasse in astronomy using the SAMI Galaxy Survey as an example.
We report results from XMM-Newton and Chandra observations of the nearby (z = 0.067) giant radio galaxy 3C 35. We find evidence for an X-ray emitting gas belt, orthogonal to and lying between the ...lobes of 3C 35, which we interpret as fossil-group gas driven outwards by the expanding radio lobes. We also detect weak emission from a second, more extended group-type environment, as well as inverse-Compton X-ray emission from the radio lobes. The morphological structure of the radio lobes and gas belt point to co-evolution. Furthermore, the radio source is powerful enough to eject galaxy-scale gas out to distances of 100kpc, and the ages of the two features are comparable (tsynch~140Myr, tbelt~80 Myr). The destruction of 3C 35's atmosphere may offer clues as to how fossil systems are regulated: radio galaxies need to be of power comparable to 3C 35 to displace and regulate fossil-group gas. We discuss the implications of the gas belt in 3C 35 in terms of AGN fuelling and feedback.
We construct a sample of 3,516 radio-loud host galaxies of active galactic nuclei (AGN) from the optical Sloan Digital Sky Survey (SDSS) and Faint Images of the Radio Sky at Twenty cm (FIRST). These ...have 1.4 GHz luminosities in the range 10E23-1025 WHz^{-1}, span redshifts 0.02<z<0.18, are brighter than r*_{petro}<17.77 mag and are constrained to `early-type' morphology in colour space (u*-r*>2.22 mag). Optical emission line ratios (at >3 sigma) are used to remove type 1 AGN and star-forming galaxies from the radio sample using BPT diagnostics. For comparison, we select a sample of 35,160 radio-quiet galaxies with the same r*-band magnitude-redshift distribution as the radio sample. We also create comparison radio and control samples derived by adding the NRAO VLA Sky Survey (NVSS) to quantify the effect of completeness on our results. We investigate the effective radii of the surface brightness profiles in the SDSS r and u bands in order to quantify any excess of blue colour in the inner region of radio galaxies. We define a ratio R=r_{e}(r)/r_{e}(u) and use maximum likelihood analysis to compare the average value of R and its intrinsic dispersion between both samples. R is larger for the radio-loud AGN sample as compared to its control counterpart, and we conclude that the two samples are not drawn from the same population at >99% significance. Given that star formation proceeds over a longer time than radio activity, the difference suggests that a subset of galaxies has the predisposition to become radio loud. We discuss host galaxy features that cause the presence of a radio-loud AGN to increase the scale size of a galaxy in red relative to blue light, including excess central blue emission, point-like blue emission from the AGN itself, and/or diffuse red emission. We favour an explanation that arises from the stellar rather than the AGN light.
In part I. I construct a sample of radio-loud active galactic nuclei (AGN) host galaxies from the optical Sloan Digital Sky Survey (SDSS) and Faint Images of the Radio Sky at Twenty cm (FIRST). These ...have 1.4GHz luminosities in the range 1023 - 1025 WHZ-l, span redshifts 0.02 < z < 0.18, are brighter than rpetro < 17.77 mag and are constrained to 'early-type' morphology in colour space (u• - r• > 2.22 mag). Optical emission-line ratios (at > 311) are used to remove type 1 AGN and star-forming galaxies from the radio sample using BPT diagnostics. For comparison, a sample of radio-quiet galaxies with the same r• -band magnitude-redshift distribution as the radio sample is selected. I also create comparison radio and control samples derived by adding the NRAO VLA Sky Survey (NVSS), to quantify the effect of completeness on the results. I investigate the effective radii of the surface brightness profiles in the SDSS r and u bands in order to quantify any excess of blue colour in the inner region of radio galaxies. A ratio is defined, R = r e( r) Ir e( u), and maximum likelihood analysis is used to compare the average value of R and its intrinsic dispersion between samples. R is larger for the radio-loud AGN sample as compared to its control counterpart, and I conclude that the two samples are not drawn from the same population at > 99% significance. I discuss host galaxy features that cause the presence of a radio-loud AGN to increase the scale size of a galaxy in red relative to blue light, including excess central blue emission driven by star formation, point-like blue emission from the AGN itself, and/or diffuse red emission. I favour an explanation that arises from the stellar rather than the AGN light. Given that iii star formation proceeds over a longer time than radio activity, the difference suggests that a subset of galaxies has a structured predisposition to become radio loud. In Part 2, I report results from Chandra and XMM-Newton observations of seven nearby (z < 0.07) radio galaxies. Each source shows evidence of an X-ray emitting gas belt, 011hogonal to and lying between the radio lobes, coincident with a deficit in radio emission. Detection of weak emission from a second, more ex tended group-type environment is also reported, as well as inverse-Compton X-ray emissions from the radio lobes in six of the sources. The X-ray emission from the nuclei correlates well with the core 5 GHz flux densities, supporting an emission origin at the base of the jet. Three high-ionization narrow-line radio galaxies in the sample show evidence for an additional absorbed component, consistent with the model in which they are fuelled by a standard thin accretion disk, heavily absorbed in X-rays when edge-on to the observer. The work extends previous detection of lobe inverse-Compton X-ray emission into the FRI regime, and the magnetic-field estimates shows that these systems are close to equipartition, or slightly electron dominated, as is found for FR II sources in other studies. The origin of the gas belts is diverse. The work concludes that two of the belts (those of NGC 7385 and NGC 6109) are galactic coronae, flattened by the expanding radio lobes. The belts of3C 192 and 4C73.08 are attributed to accumulated gas from merging groups of galaxies residing within the gas belt. For 3C 386, the belt is consistent with a hot gas halo surrounding an isolated field elliptical In the case of 3C 35 and 3C 98, the gas belt is interpreted as fossil -group gas driven outwards by the expanding radio lobes. The morphological structure of the radio lobes and gas belt point to co-evolution. Furthermore, the radio sources are powerful enough to eject galaxy-scale gas out to the edges of the gas belts, and the ages of the belts and radio structures are comparable in both sources. The destruction of 3C 35 and 3C 98's atmospheres may offer clues as to how fossil systems are regulated: radio galaxies may need to be within a particular range of intermediate powers to displace and regulate fossil-group gas. I discuss the implications of the gas belts in 3C 35 and 3C 98 in terms of AGN fuelling and feedback.
We present the second major release of data from the SAMI Galaxy Survey. Data Release Two includes data for 1559 galaxies, about 50% of the full survey. Galaxies included have a redshift range 0.004 ...< z < 0.113 and a large stellar mass range 7.5 < log (M_star/M_sun) < 11.6. The core data for each galaxy consist of two primary spectral cubes covering the blue and red optical wavelength ranges. For each primary cube we also provide three spatially binned spectral cubes and a set of standardised aperture spectra. For each core data product we provide a set of value-added data products. This includes all emission line value-added products from Data Release One, expanded to the larger sample. In addition we include stellar kinematic and stellar population value-added products derived from absorption line measurements. The data are provided online through Australian Astronomical Optics' Data Central. We illustrate the potential of this release by presenting the distribution of ~350,000 stellar velocity dispersion measurements from individual spaxels as a function of R/R_e, divided in four galaxy mass bins. In the highest stellar mass bin (log (M_star/M_sun)>11), the velocity dispersion strongly increases towards the centre, whereas below log (M_star/M_sun)<10 we find no evidence for a clear increase in the central velocity dispersion. This suggests a transition mass around log (M_star/M_sun) ~10 for galaxies with or without a dispersion-dominated bulge.
We present the first major release of data from the SAMI Galaxy Survey. This data release focuses on the emission-line physics of galaxies. Data Release One includes data for 772 galaxies, about 20% ...of the full survey. Galaxies included have the redshift range 0.004 < z < 0.092, a large mass range (7.6 < log(Mstellar/M\(_\odot\)) < 11.6), and star-formation rates of 10^-4 to 10^1\ M\(_\odot\)/yr. For each galaxy, we include two spectral cubes and a set of spatially resolved 2D maps: single- and multi-component emission-line fits (with dust extinction corrections for strong lines), local dust extinction and star-formation rate. Calibration of the fibre throughputs, fluxes and differential-atmospheric-refraction has been improved over the Early Data Release. The data have average spatial resolution of 2.16 arcsec (FWHM) over the 15~arcsec diameter field of view and spectral (kinematic) resolution R=4263 (sigma=30km/s) around Halpha. The relative flux calibration is better than 5\% and absolute flux calibration better than \(\pm0.22\)~mag, with the latter estimate limited by galaxy photometry. The data are presented online through the Australian Astronomical Observatory's Data Central.
We present the GAMA Panchromatic Data Release (PDR) constituting over 230deg\(^2\) of imaging with photometry in 21 bands extending from the far-UV to the far-IR. These data complement our ...spectroscopic campaign of over 300k galaxies, and are compiled from observations with a variety of facilities including: GALEX, SDSS, VISTA, WISE, and Herschel, with the GAMA regions currently being surveyed by VST and scheduled for observations by ASKAP. These data are processed to a common astrometric solution, from which photometry is derived for 221,373 galaxies with r<19.8 mag. Online tools are provided to access and download data cutouts, or the full mosaics of the GAMA regions in each band. We focus, in particular, on the reduction and analysis of the VISTA VIKING data, and compare to earlier datasets (i.e., 2MASS and UKIDSS) before combining the data and examining its integrity. Having derived the 21-band photometric catalogue we proceed to fit the data using the energy balance code MAGPHYS. These measurements are then used to obtain the first fully empirical measurement of the 0.1-500\(\mu\)m energy output of the Universe. Exploring the Cosmic Spectral Energy Distribution (CSED) across three time-intervals (0.3-1.1Gyr, 1.1-1.8~Gyr and 1.8---2.4~Gyr), we find that the Universe is currently generating \((1.5 \pm 0.3) \times 10^{35}\) h\(_{70}\) W Mpc\(^{-3}\), down from \((2.5 \pm 0.2) \times 10^{35}\) h\(_{70}\) W Mpc\(^{-3}\) 2.3~Gyr ago. More importantly, we identify significant and smooth evolution in the integrated photon escape fraction at all wavelengths, with the UV escape fraction increasing from 27(18)% at z=0.18 in NUV(FUV) to 34(23)% at z=0.06. The GAMA PDR will allow for detailed studies of the energy production and outputs of individual systems, sub-populations, and representative galaxy samples at \(z<0.5\). The GAMA PDR can be found at: http://gama-psi.icrar.org/
PDF
