Citation for published item:viskeD tF nd fldryD sFuF nd hriverD FF nd u'sD FtF nd elpslnD wF nd endreD iF nd froughD F nd gluverD wFiF nd qrootesD wFF nd qunwrdhnD wFvFF nd uelvinD vFF nd vovedyD tF nd oothmD eFFqF nd ylorD iFxF nd fmfordD FF nd flndErwthornD tF nd frownD wFtFsF nd hrinkwterD wFtF nd ropkinsD eFwF nd weyerD wFtF nd xorergD F nd eokD tFeF nd egiusD xFuF nd endrewsD FuF nd fuerD eFiF nd ghingD tFrFF nd gollessD wF nd gonselieD gFtF nd groomD FwF nd hviesD vFtFwF nd he roprisD F nd hunneD vF nd irdleyD iFwF nd illisD F nd posterD gF nd prenkD gFF nd r¤ ußlerD fF nd rolwerdD fFF nd rowlettD gF nd srrD rF nd trvisD wFtF nd tonesD hFrF nd u)eD FF nd veyD gFqF nd vngeD F nd vrEv¡ opezD wFeF nd v¡ opezE¡ nhezD ¡ eFF nd wddoxD F nd wdoreD fFpF nd wxughtEoertsD F nd wo'ettD eFtF nd xiholD FgF nd ywersD wFF nd lmrD hF nd ennyD FtF nd hillippsD F nd imletD uFeF nd opesuD gFgF nd resottD wF nd rotorD F nd dlerD iFwF nd nsomD eFiF nd eiertD wF nd hrpD F nd utherlndD F nd ¡ zquezEwtD tFeF nd vn umpenD iF nd ilkinsD FwF nd illimsD F nd rightD eFrF @PHISA 9qlxy end wss essemly @qeweA X end of survey report nd dt relese PF9D wonthly noties of the oyl estronomil oietyFD RSP @PAF ppF PHVUEPIPTF Further information on publisher's website: Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACTThe Galaxy And Mass Assembly (GAMA) survey is one of the largest contemporary spectroscopic surveys of low redshift galaxies. Covering an area of ∼286 deg 2 (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 p...
We measure the projected 2-point correlation function of galaxies in the 180 deg 2 equatorial regions of the GAMA II survey, for four different redshift slices between z = 0.0 and z = 0.5. To do this we further develop the Cole (2011) method of producing suitable random catalogues for the calculation of correlation functions. We find that more r-band luminous, more massive and redder galaxies are more clustered. We also find that red galaxies have stronger clustering on scales less than ∼ 3 h −1 Mpc. We compare to two different versions of the GALFORM galaxy formation model, Lacey et al (in prep.) and Gonzalez-Perez et al. (2014), and find that the models reproduce the trend of stronger clustering for more massive galaxies. However, the models under predict the clustering of blue galaxies, can incorrectly predict the correlation function on small scales and under predict the clustering in our sample of galaxies with ∼ 3L * r . We suggest possible avenues to explore to improve these clustering predictions. The measurements presented in this paper can be used to test other galaxy formation models, and we make the measurements available online to facilitate this.
We have searched for active galactic nuclei (AGNs) in K+A galaxies, using multiwavelength imaging and spectroscopy in the Boötes field of the NOAO Deep Wide-Field Survey. The K+A galaxies, which have had their star formation rapidly truncated, are selected via their strong Balmer absorption lines and weak Hα emission. Our sample consists of 24 K+A galaxies selected from 6594 0.10 < z < 0.35 galaxies brighter than I = 20 with optical spectroscopy from the AGN and Galaxy Evolution Survey. Two thirds of the K+A galaxies are likely ongoing galaxy mergers, with nearby companion galaxies or tidal tails. Galaxy mergers may be responsible for the truncation of star formation, or we are observing the aftermath of merger triggered starbursts. As expected, the optical colors of K+A galaxies largely fall between blue galaxies with ongoing star formation and red passive galaxies. However, only 1% of the galaxies with colors between the red and blue populations are K+A galaxies, and we conclude that the truncation of star formation in K+A galaxies must have been unusually abrupt ( 100 Myr). We examined the AGN content of K+A galaxies with both optical emission-line ratios (BPT diagrams) and Chandra X-ray imaging. At least half of all K+A galaxies display the optical emission-line ratios of AGNs, and a third of M R < −22 K+A galaxies host AGNs with X-ray luminosities of ∼10 42 erg s −1 . The faintest K+A galaxies do not show clear evidence for hosting AGNs, having emission-line ratios consistent with photoionization by massive stars and few X-ray detections. We speculate that two mechanisms may be responsible for the truncation of star formation in K+A galaxies, with AGN feedback only playing a role in M R −20.5 galaxies.
We have used the AAOMEGA spectrograph to obtain R ∼ 1500 spectra of 714 stars that are members of two red clumps in the Plaut Window Galactic bulge field (l, b) = 0 • , −8 • . We discern no difference between the clump populations based on radial velocities or abundances measured from the Mgb index. The velocity dispersion has a strong trend with Mgb-index metallicity, in the sense of a declining velocity dispersion at higher metallicity. We also find a strong trend in mean radial velocity with abundance. Our red clump sample shows distinctly different kinematics for stars with [Fe/H] < −1, which may plausibly be attributable to a minority classical bulge or inner halo population. The transition between the two groups is smooth. The chemo-dynamical properties of our sample are reminiscent of those of the Milky Way globular cluster system. If correct, this argues for no bulge/halo dichotomy and a relatively rapid star formation history. Large surveys of the composition and kinematics of the bulge clump and red giant branch are needed to define further these trends.
As galaxy formation and evolution over long cosmic time-scales depends to a large degree on the structure of the universe, the assembly history of galaxies is potentially a powerful approach for learning about the universe itself. In this paper we examine the merger history of dark matter halos based on the Extended Press-Schechter formalism as a function of cosmological parameters, redshift and halo mass. We calculate how major halo mergers are influenced by changes in the cosmological values of Ω m , Ω Λ , σ 8 , the dark matter particle temperature (warm vs. cold dark matter), and the value of a constant and evolving equation of state parameter w(z). We find that the merger fraction at a given halo mass varies by up to a factor of three for halos forming under the assumption of Cold Dark Matter, within different underling cosmological parameters. We find that the current measurements of the merger history, as measured through observed galaxy pairs as well as through structure, are in agreement with the concordance cosmology with the current best fit giving 1 − Ω m = Ω Λ = 0.84 +0.16 −0.17 . To obtain a more accurate constraint competitive with recently measured cosmological parameters from Planck and WMAP requires a measured merger accuracy of δf m ∼ 0.01, implying surveys with an accurately measured merger history over 2 -20 deg 2 , which will be feasible with the next generation of imaging and spectroscopic surveys such as Euclid and LSST.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.