Browsing by Author "Brough, Sarah"

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    Galaxy and Mass Assembly (GAMA): active galactic nuclei in pairs of galaxies
    (OXFORD UNIV PRESS, 2017) Gordon, Yjan A.; Owers, Matt S.; Pimbblet, Kevin A.; Croom, Scott M.; Alpaslan, Mehmet; Baldry, Ivan K.; Brough, Sarah; Brown, Michael J. I.; Cluver, Michelle E.; Conselice, Christopher J.; Davies, Luke J. M.; Holwerda, Benne W.; Hopkins, Andrew M.; Gunawardhana, Madusha L. P.; Loveday, Jonathan; Taylor, Edward N.; Wang, Lingyu
    There exist conflicting observations on whether or not the environment of broad-and narrowline active galatic nuclei (AGN) differ and this consequently questions the validity of the AGN unification model. The high spectroscopic completeness of the Galaxy and Mass Assembly (GAMA) survey makes it ideal for a comprehensive analysis of the close environment of galaxies. To exploit this, and conduct a comparative analysis of the environment of broad-and narrow-line AGN within GAMA, we use a double-Gaussian emission line fitting method to model the more complex line profiles associated with broad-line AGN. We select 209 type 1 (i.e. unobscured), 464 type 1.5-1.9 (partially obscured), and 281 type 2 (obscured) AGN within the GAMA II data base. Comparing the fractions of these with neighbouring galaxies out to a pair separation of 350 kpc h(-1) and triangle z < 0.012 shows no difference between AGN of different type, except at separations less than 20 kpc h(-1) where our observations suggest an excess of type 2 AGN in close pairs. We analyse the properties of the galaxies neighbouring our AGN and find no significant differences in colour or the star formation activity of these galaxies. Further to this, we find that Sigma(5) is also consistent between broad-and narrow-line AGN. We conclude that the observations presented here are consistent with AGN unification.
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    Optimization of the Observing Cadence for the Rubin Observatory Legacy Survey of Space and Time: A Pioneering Process of Community-focused Experimental Design
    (2022) Bianco, Federica B.; Ivezić, Željko; Jones, R. Lynne; Graham, Melissa L.; Marshall, Phil; Saha, Abhijit; Strauss, Michael A.; Yoachim, Peter; Ribeiro, Tiago; Anguita, Timo; Bauer, A. E.; Bauer, Franz E.; Bellm, Eric C.; Blum, Robert D.; Brandt, William N.; Brough, Sarah; Catelan, Márcio; Clarkson, William I.; Connolly, Andrew J.; Gawiser, Eric; Gizis, John E.; Hložek, Renée; Kaviraj, Sugata; Liu, Charles T.; Lochner, Michelle; Mahabal, Ashish A.; Mandelbaum, Rachel; McGehee, Peregrine; Neilsen, Eric H., Jr.; Olsen, Knut A. G.; Peiris, Hiranya V.; Rhodes, Jason; Richards, Gordon T.; Ridgway, Stephen; Schwamb, Megan E.; Scolnic, Dan; Shemmer, Ohad; Slater, Colin T.; Slosar, Anže; Smartt, Stephen J.; Strader, Jay; Street, Rachel; Trilling, David E.; Verma, Aprajita; Vivas, A. K.; Wechsler, Risa H.; Willman, Beth
    Vera C. Rubin Observatory is a ground-based astronomical facility under construction, a joint project of the National Science Foundation and the U.S. Department of Energy, designed to conduct a multipurpose 10 yr optical survey of the Southern Hemisphere sky: the Legacy Survey of Space and Time. Significant flexibility in survey strategy remains within the constraints imposed by the core science goals of probing dark energy and dark matter, cataloging the solar system, exploring the transient optical sky, and mapping the Milky Way. The survey's massive data throughput will be transformational for many other astrophysics domains and Rubin's data access policy sets the stage for a huge community of potential users. To ensure that the survey science potential is maximized while serving as broad a community as possible, Rubin Observatory has involved the scientific community at large in the process of setting and refining the details of the observing strategy. The motivation, history, and decision-making process of this strategy optimization are detailed in this paper, giving context to the science-driven proposals and recommendations for the survey strategy included in this Focus Issue....
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    VEGAS: A VST Early-type GAlaxy Survey: VI. Diffuse light in HCG 86 as seen from the ultra-deep VEGAS images
    (2021) Ragusa, Rossella; Spavone, Marilena; Iodice, Enrichetta; Brough, Sarah; Raj, Maria Angela; Paolillo, Maurizio; Cantiello, Michele; Forbes, Duncan A.; La Marca, Antonio; D'Ago, Giuseppe; Rampazzo, Roberto; Schipani, Pietro
    Context. In this paper, we present ultra-deep images of the compact group of galaxies HCG 86 as part of the VEGAS survey.Aims. Our main goals are to estimate the amount of intra-group light (IGL) as well as to study the light and colour distributions in order to address the main formation process of the IGL component in groups of galaxies.Methods. We derived the azimuthally averaged surface brightness profiles in the g, r, and i bands with g-r and r-i average colours and colour profiles for all group members. By fitting the light distribution, we extrapolated the contribution of the stellar halos plus the diffuse light from the brightest component of each galaxy. The results are compared with theoretical predictions.Results. The long integration time and wide area covered make our data reach deeper than previous literature studies of the IGL in compact groups of galaxies and allow us to produce an extended (similar to 160 kpc) map of the IGL, down to a surface brightness level of similar to 30 mag arcsec(-2) in the g band. The IGL in HCG 86 is mainly in diffuse form and has average colours of g-r similar to 0.8 mag and r-i similar to 0.4 mag. The fraction of IGL in HCG 86 is similar to 16% of the total luminosity of the group, and this is consistent with estimates available for other compact groups and loose groups of galaxies of similar virial masses. A weak trend is present between the amount of IGL and the early-type to late-type galaxy ratio. A lack of a clear correlation is found between the amount of diffuse light and the cluster or group virial mass.Conclusions. By comparing the IGL fraction and colours with those predicted by simulations, the amount of IGL in HCG 86 would be the result of the disruption of satellites at an epoch of z similar to 0.4. At this redshift, the observed colours are consistent with the scenario where the main contribution to the mass of the IGL comes from the intermediate-to-massive galaxies (10(10)<= M-*<= 10(11) M-circle dot).