The Galaxy And Mass Assembly (GAMA) survey is one of the largest contemporary spectroscopic surveys of low redshift galaxies. Covering an area of ∼286 deg2 (split among five survey regions) down to a ...limiting magnitude of r < 19.8 mag, we have collected spectra and reliable redshifts for 238 000 objects using the AAOmega spectrograph on the Anglo-Australian Telescope. In addition, we have assembled imaging data from a number of independent surveys in order to generate photometry spanning the wavelength range 1 nm–1 m. Here, we report on the recently completed spectroscopic survey and present a series of diagnostics to assess its final state and the quality of the redshift data. We also describe a number of survey aspects and procedures, or updates thereof, including changes to the input catalogue, redshifting and re-redshifting, and the derivation of ultraviolet, optical and near-infrared photometry. Finally, we present the second public release of GAMA data. In this release, we provide input catalogue and targeting information, spectra, redshifts, ultraviolet, optical and near-infrared photometry, single-component Sérsic fits, stellar masses, Hα-derived star formation rates, environment information, and group properties for all galaxies with r < 19.0 mag in two of our survey regions, and for all galaxies with r < 19.4 mag in a third region (72 225 objects in total). The data base serving these data is available at http://www.gama-survey.org/.
The modification of star formation (SF) in galaxy interactions is a complex process, with SF observed to be both enhanced in major mergers and suppressed in minor pair interactions. Such changes ...likely to arise on short time-scales and be directly related to the galaxy–galaxy interaction time. Here we investigate the link between dynamical phase and direct measures of SF on different time-scales for pair galaxies, targeting numerous star- formation rate (SFR) indicators and comparing to pair separation, individual galaxy mass and pair mass ratio. We split our sample into the higher (primary) and lower (secondary) mass galaxies in each pair and find that SF is indeed enhanced in all primary galaxies but suppressed in secondaries of minor mergers. We find that changes in SF of primaries are consistent in both major and minor mergers, suggesting that SF in the more massive galaxy is agnostic to pair mass ratio. We also find that SF is enhanced/suppressed more strongly for short-duration SFR indicators (e.g. Hα), highlighting recent changes to SF in these galaxies, which are likely to be induced by the interaction. We propose a scenario where the lower mass galaxy has its SF suppressed by gas heating or stripping, while the higher mass galaxy has its SF enhanced, potentially by tidal gas turbulence and shocks. This is consistent with the seemingly contradictory observations for both SF suppression and enhancement in close pairs.
We present a meta-analysis of star formation rate (SFR) indicators in the Galaxy And Mass Assembly (GAMA) survey, producing 12 different SFR metrics and determining the SFR-M... relation for each. We ...compare and contrast published methods to extract the SFR from each indicator, using a well-defined local sample of morphologically selected spiral galaxies, which excludes sources which potentially have large recent changes to their SFR. The different methods are found to yield SFR-M... relations with inconsistent slopes and normalizations, suggesting differences between calibration methods. The recovered SFR-M... relations also have a large range in scatter which, as SFRs of the targets may be considered constant over the different time-scales, suggests differences in the accuracy by which methods correct for attenuation in individual targets. We then recalibrate all SFR indicators to provide new, robust and consistent luminosity-to-SFR calibrations, finding that the most consistent slopes and normalizations of the SFR-M... relations are obtained when recalibrated using the radiation transfer method of Popescu et al. These new calibrations can be used to directly compare SFRs across different observations, epochs and galaxy populations. We then apply our calibrations to the GAMA II equatorial data set and explore the evolution of star formation in the local Universe. We determine the evolution of the normalization to the SFR-M... relation from 0 < z < 0.35 -- finding consistent trends with previous estimates at 0.3 < z < 1.2. We then provide the definitive z < 0.35 cosmic star formation history, SFR-M... relation and its evolution over the last 3 billion years. (ProQuest: ... denotes formulae/symbols omitted.)
A set of “early warning responses”, measured as biomarkers of exposure and effect, was applied in the marine bioindicator Hediste diversicolor, in a way to assess the environmental quality of ...sediment affected by pharmaceutical contamination. Sublethal responses were determined in the sea-worms after 14-days of exposure to sediment spiked with some of the most representative pharmaceutical products found in the environment: carbamazepine (CBZ), ibuprofen (IBP), fluoxetine (FX), 17α-ethynylestradiol (EE2) and propranolol (PRO), including the environmental concentrations. Phases I (ethoxyresorufin O-deethylase – EROD and dibenzylfluorescein dealkylase – DBF) and II (glutathione S-transferase – GST) of the metabolism, antioxidant system (glutathione peroxidase – GPX and glutathione reductase – GR), neurotoxicity (acetylcholinesterase – AChE) and oxidative effects (lipid peroxidation – LPO and DNA damage strand breaks) were selected to evaluate the sublethal responses in the sea-worms. FX, EE2 and PRO were detoxified by the phase I of the metabolism (EROD activity). On the other hand, phase II (GST-activity) did not respond in sea-worms exposed to pharmaceutical products, except for the environmental concentrations of CBZ (activation) and PRO (deactivation). Neurotoxicity was induced in sea-worms exposed to EE2 (only the environmental concentrations), FX, IBP and CBZ. Oxidative effect determined as LPO increased in sea-worms exposed to environmental concentrations of IBP, EE2 and PRO. Genetic damage increased in sea-worms exposed to IBP and diminished for FX, EE2 and PRO. Our results indicated the toxicity of pharmaceutical products and recommended the battery of biomarkers and the bioindicator specie H. diversicolor for the environmental quality assessment of sediment affected by pharmaceutical contamination.
•Polychaetes were exposed for 14-days to pharmaceuticals-spiked sediments.•Carbamazepine, ibuprofen, fluoxetine, 17α-ethynylestradiol, propranolol.•Biomarkers were a suitable tool to evaluate possible risks of pharmaceuticals.•Pharmaceuticals were neurotoxic for sea-worms exposed to spiked-sediments.•Oxidative effect was observed in sea-worms exposed to pharmaceuticals.
Fetal growth plays a role in programming of adult cardiometabolic disorders, which in men, are associated with lowered testosterone levels. Fetal growth and fetal androgen exposure can also ...predetermine testosterone levels in men, although how is unknown, because the adult Leydig cells (ALCs) that produce testosterone do not differentiate until puberty. To explain this conundrum, we hypothesized that stem cells for ALCs must be present in the fetal testis and might be susceptible to programming by fetal androgen exposure during masculinization. To address this hypothesis, we used ALC ablation/regeneration to identify that, in rats, ALCs derive from stem/progenitor cells that express chicken ovalbumin upstream promoter transcription factor II. These stem cells are abundant in the fetal testis of humans and rodents, and lineage tracing in mice shows that they develop into ALCs. The stem cells also express androgen receptors (ARs). Reduction in fetal androgen action through AR KO in mice or dibutyl phthalate (DBP) -induced reduction in intratesticular testosterone in rats reduced ALC stem cell number by ∼40% at birth to adulthood and induced compensated ALC failure (low/normal testosterone and elevated luteinizing hormone). In DBP-exposed males, this failure was probably explained by reduced testicular steroidogenic acute regulatory protein expression, which is associated with increased histone methylation (H3K27me3) in the proximal promoter. Accordingly, ALCs and ALC stem cells immunoexpressed increased H3K27me3, a change that was also evident in ALC stem cells in fetal testes. These studies highlight how a key component of male reproductive development can fundamentally reprogram adult hormone production (through an epigenetic change), which might affect lifetime disease risk.
A full appreciation of the role played by gas metallicity (Z), star formation rate (SFR) and stellar mass (M
*) is fundamental to understanding how galaxies form and evolve. The connections between ...these three parameters at different redshifts significantly affect galaxy evolution, and thus provide important constraints for galaxy evolution models. Using data from the Sloan Digital Sky Survey-Data Release 7 (SDSS-DR7) and the Galaxy and Mass Assembly (GAMA) surveys, we study the relationships and dependences between SFR, Z and M
*, as well as the Fundamental Plane for star-forming galaxies. We combine both surveys using volume-limited samples up to a redshift of z 0.36. The GAMA and SDSS surveys complement each other when analysing the relationships between SFR, M
* and Z. We present evidence for SFR and metallicity evolution to z ∼ 0.2. We study the dependences between SFR, M
*, Z and specific SFR (SSFR) on the M
*-Z, M
*-SFR, M
*-SSFR, Z-SFR and Z-SSFR relations, finding strong correlations between all. Based on those dependences, we propose a simple model that allows us to explain the different behaviour observed between low- and high-mass galaxies. Finally, our analysis allows us to confirm the existence of a Fundamental Plane, for which M
* = f(Z, SFR) in star-forming galaxies.
Ultra-hot Jupiters are emerging as a new class of exoplanets. Studying their chemical compositions and temperature structures will improve our understanding of their mass loss rate as well as their ...formation and evolution. We present the detection of ionized calcium in the two hottest giant exoplanets – KELT-9b and WASP-33b. By using transit datasets from CARMENES and HARPS-N observations, we achieved high-confidence-level detections of Ca II using the cross-correlation method. We further obtain the transmission spectra around the individual lines of the Ca II H&K doublet and the near-infrared triplet, and measure their line profiles. The Ca II H&K lines have an average line depth of 2.02 ± 0.17% (effective radius of 1.56 Rp) for WASP-33b and an average line depth of 0.78 ± 0.04% (effective radius of 1.47 Rp) for KELT-9b, which indicates that the absorptions are from very high upper-atmosphere layers close to the planetary Roche lobes. The observed Ca II lines are significantly deeper than the predicted values from the hydrostatic models. Such a discrepancy is probably a result of hydrodynamic outflow that transports a significant amount of Ca II into the upper atmosphere. The prominent Ca II detection with the lack of significant Ca I detection implies that calcium is mostly ionized in the upper atmospheres of the two planets.
High resolution transit spectroscopy has proven to be a reliable technique for the characterization of the chemical composition of exoplanet atmospheres. Taking advantage of the broad spectral ...coverage of the CARMENES spectrograph, we initiated a survey aimed at characterizing a broad range of planetary systems. Here, we report our observations of three transits of GJ 3470 b with CARMENES in search of He (2
3
S) absorption. On one of the nights, the He
I
region was heavily contaminated by OH
−
telluric emission and, thus, it was not useful for our purposes. The remaining two nights had a very different signal-to-noise ratio (S/N) due to weather. They both indicate the presence of He (2
3
S) absorption in the transmission spectrum of GJ 3470 b, although a statistically valid detection can only be claimed for the night with higher S/N. For that night, we retrieved a 1.5 ± 0.3% absorption depth, translating into a
R
p
(
λ
)∕
R
p
= 1.15 ± 0.14 at this wavelength. Spectro-photometric light curves for this same night also indicate the presence of extra absorption during the planetary transit with a consistent absorption depth. The He (2
3
S) absorption is modeled in detail using a radiative transfer code, and the results of our modeling efforts are compared to the observations. We find that the mass-loss rate,
Ṁ
, is confined to a range of 3 × 10
10
g s
−1
for
T
= 6000 K to 10 × 10
10
g s
−1
for
T
= 9000 K. We discuss the physical mechanisms and implications of the He
I
detection in GJ 3470 b and put it in context as compared to similar detections and non-detections in other Neptune-size planets. We also present improved stellar and planetary parameter determinations based on our visible and near-infrared observations.
Abstract
We present the calibration between the dust continuum luminosity and interstellar gas content obtained from the Valparaíso ALMA Line Emission Survey (VALES) sample of 67 main-sequence ...star-forming galaxies at 0.02 < z < 0.35. We use CO(1–0) observations from the Atacama Large Millimetre/submillimetre Array to trace the molecular gas mass, M
H
2, and estimate the rest-frame monochromatic luminosity at 850 μm,
$L_{\nu _{850}}$
, by extrapolating the dust continuum from magphys modelling of the far-ultraviolet to submillimetre spectral energy distribution sampled by the Galaxy And Mass Assembly survey. Adopting αCO = 6.5 (K km s−1 pc2)−1, the average ratio of
$L_{\nu _{850}}$
/M
H
2 = (6.4 ± 1.4)× 1019 erg s−1 Hz−1 M
$_{{\odot }}^{-1}$
, in excellent agreement with literature values. We obtain a linear fit of
$\log _{10} \left({M}_{\mathrm{H}_{2}}/{\mathrm{M}_{{\odot }}}\right) = (0.92\pm 0.02) \log _{10} (L_{\nu _{850}}/{\mathrm{erg}\,\mathrm{s}^{-1}\,\mathrm{Hz}^{-1}})-(17.31\pm 0.59)$
. We provide relations between
$L_{\nu _{850}}$
, M
H
2 and M
ISM when combining the VALES and literature samples, and adopting a Galactic αCO value.
Aims.
We study the effect of disequilibrium processes (photochemistry and vertical transport) on mixing ratio profiles of neutral species and on the simulated spectra of a hot Jupiter exoplanet that ...orbits stars of various spectral types. We additionally address the impact of stellar activity that should be present, to various degrees, in all stars with convective envelopes.
Methods.
We used the VULCAN chemical kinetic code to compute number densities of species in irradiated planetary atmospheres. The temperature-pressure profile of the atmosphere was computed with the HELIOS code. We also utilized the
τ
-REx forward model to predict the spectra of planets in primary and secondary eclipses. In order to account for the stellar activity, we made use of the observed solar extreme ultraviolet (XUV) spectrum taken from Virtual Planetary Laboratory as a proxy for an active sun-like star.
Results.
We find large changes in the mixing ratios of most chemical species in planets orbiting A-type stars, which radiate strong XUV flux thereby inducing a very effective photodissociation. For some species, these changes can propagate very deep into the planetary atmosphere to pressures of around 1 bar. To observe disequilibrium chemistry we favor hot Jupiters with temperatures
T
eq
= 1000 K and ultra-hot Jupiters, with
T
eq
≈ 3000 K,which also have temperature inversion in their atmospheres. On the other hand, disequilibrium calculations predict no noticeable changes in spectra of planets with intermediate temperatures. We also show that stellar activity similar to that of the modern Sun drives important changes in mixing ratio profiles of atmospheric species. However, these changes take place at very high atmospheric altitudes and thus do not affect predicted spectra. Finally, we estimate that the effect of disequilibrium chemistry in planets orbiting nearby bright stars could be robustly detected and studied with future missions with spectroscopic capabilities in infrared such as
James Webb
Space Telescope and ARIEL.
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