Browsing by Author "Baker, Andrew J."
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- ItemGMRT 610 MHz observations of galaxy clusters in the ACT equatorial sample(2019) Knowles, Kenda; Baker, Andrew J.; Bond, J. Richard; Gallardo, Patricio A.; Gupta, Neeraj; Hilton, Matt; Hughes, John P.; Intema, Huib; Lopez-Caraballo, Carlos H.; Moodley, Kavilan; Schmitt, Benjamin L.; Sievers, Jonathan; Sifon, Cristobal; Wollack, EdwardWe present Giant Metrewave Radio Telescope (GMRT) 610 MHz observations of 14 Atacama Cosmology Telescope (ACT) clusters, including new data for nine. The sample includes 73 per cent of ACT equatorial clusters with M-500 > 5 x 10(14) M-circle dot. We detect diffuse emission in three of these (27(-14)(+20) per cent): we detect a radio minihalo in ACT-CL J0022.2-0036 at z = 0.8, making it the highest redshift minihalo known; we detect potential radio relic emission in ACT-CL J0014.9-0057 (z = 0.533); and we confirm the presence of a radio halo in low-mass cluster ACT-CL J0256.5+0006, with flux density S-610 = 6.3 +/- 0.4 mJy. We also detect residual diffuse emission inACT-CL J0045.9-0152 (z = 0.545), which we cannot conclusively classify. For systems lacking diffuse radio emission, we determine radio halo upper limits in two ways and find via survival analysis that these limits do not significantly affect radio power scaling relations. Several clusters with no diffuse emission detection are known or suspected mergers, based on archival X-ray and/or optical measures; given the limited sensitivity of our observations, deeper observations of these disturbed systems are required in order to rule out the presence of diffuse emission consistent with known scaling relations. In parallel with our diffuse emission results, we present catalogues of individual radio sources, including a few interesting extended sources. Our study represents the first step towards probing the occurrence of diffuse emission in high-redshift (z greater than or similar to 0.5) clusters, and serves as a pilot for statistical studies of larger cluster samples with the new radio telescopes available in the pre-SKA era.
- ItemHerschel and ALMA observations of massive SZE-selected clusters(2018) Wu, John F.; Aguirre, Paula; Baker, Andrew J.; Devlin, Mark J.; Hilton, Matt; Hughes, John P.; Infante Lira, Leopoldo; Lindner, Robert R.; Sifón, Cristóbal
- ItemThe Atacama Cosmology Telescope : the LABOCA/ACT Survey of Clusters at All Redshifts(2015) Lindner, Robert; Aguirre Aparicio, Paula; Baker, Andrew J.; Bond, J. Richard; Crichton, Devin; Devlin, Mark J.; Essinger-Hileman, Thomas; Gallardo, Patricio; Gralla, Megan B.; Hilton, Matt
- ItemThe atacama cosmology telescope : The stellar content of galaxy clusters selected using the sunyaev-zel'dovich effect(2013) Hilton, Matt; Hasselfield, Matthew; Sifon, Cristobal; Baker, Andrew J.; Barrientos, Luis Felipe; Battaglia, Nicholas; Bond, J. Richard; Crichton, Devin; Das, Sudeep; Infante Lira, Leopoldo
- ItemThe Atacama Cosmology Telescope: CO(J=3-2) Mapping and Lens Modeling of an ACT-selected Dusty Star-forming Galaxy(2019) Rivera, Jesus; Baker, Andrew J.; Gallardo, Patricio A.; Gralla, Megan B.; Harris, Andrew, I; Huffenberger, Kevin M.; Hughes, John P.; Keeton, Charles R.; Lopez-Caraballo, Carlos H.; Marriage, Tobias A.; Partridge, Bruce; Sievers, Jonathan L.; Tagore, Amitpal S.; Walter, Fabian; Weiss, Axel; Wollack, Edward J.We report Northern Extended Millimeter Array CO(J = 3 - 2) observations of the dusty star-forming galaxy ACT-S J020941+001557 at z = 2.5528, which was detected as an unresolved source in the Atacama Cosmology Telescope (ACT) equatorial survey. Our spatially resolved spectral line data support the derivation of a gravitational lens model from 37 independent velocity channel maps using a pixel-based algorithm, from which we infer a velocity-dependent magnification factor mu approximate to 7-22 with a luminosity-weighted mean approximate to 13. The resulting source-plane reconstruction is consistent with a rotating disk, although other scenarios cannot be ruled out by our data. After correction for lensing, we derive a line luminosity LCO(3-2)' = (5.53 +/- 0.69) x 10(10) K km s(-1) pc(2), a cold gas mass M-gas = (3.86 +/- 0.33) x 10(10) M-circle dot, a dynamical mass M-dyn sin(2) i = 3.9(-1.5)(+1.8) x 10(10) M-circle dot, and a gas mass fraction f(gas) csc(2) i = 1.0(-0.4)(+0.8). The line brightness temperature ratio of r(3,1) approximate to 1.6 relative to a Green Bank Telescope CO(J = 1 - 0) detection may be elevated by a combination of external heating of molecular clouds, differential lensing, and/or pointing errors.
- ItemThe Atacama Cosmology Telescope: Physical Properties and Purity of a Galaxy Cluster Sample Selected via the Sunyaev-Zel'dovich Effect(2010) Menanteau, Felipe; González, Jorge; Juin, Jean-Baptiste; Marriage, Tobias A.; Reese, Erik D.; Acquaviva, Viviana; Aguirre, Paula; Appel, John William; Baker, Andrew J.; Barrientos, L. Felipe; Battistelli, Elia S.; Bond, J. Richard; Das, Sudeep; Deshpande, Amruta J.; Devlin, Mark J.; Dicker, Simon; Dunkley, Joanna; Dünner, Rolando; Essinger-Hileman, Thomas; Fowler, Joseph W.; Hajian, Amir; Halpern, Mark; Hasselfield, Matthew; Hernández-Monteagudo, Carlos; Hilton, Matt; Hincks, Adam D.; Hlozek, Renée; Huffenberger, Kevin M.; Hughes, John P.; Infante, Leopoldo; Irwin, Kent D.; Klein, Jeff; Kosowsky, Arthur; Lin, Yen-Ting; Marsden, Danica; Moodley, Kavilan; Niemack, Michael D.; Nolta, Michael R.; Page, Lyman A.; Parker, Lucas; Partridge, Bruce; Sehgal, Neelima; Sievers, Jon; Spergel, David N.; Staggs, Suzanne T.; Swetz, Daniel; Switzer, Eric; Thornton, Robert; Trac, Hy; Warne, Ryan; Wollack, EdWe present optical and X-ray properties for the first confirmed galaxy cluster sample selected by the Sunyaev-Zel'dovich effect (SZE) from 148 GHz maps over 455 deg(2) of sky made with the Atacama Cosmology Telescope (ACT). These maps, coupled with multi-band imaging on 4 m class optical telescopes, have yielded a sample of 23 galaxy clusters with redshifts between 0.118 and 1.066. Of these 23 clusters, 10 are newly discovered. The selection of this sample is approximately mass limited and essentially independent of redshift. We provide optical positions, images, redshifts, and X-ray fluxes and luminosities for the full sample, and X-ray temperatures of an important subset. The mass limit of the full sample is around 8.0 x 10(14) M-circle dot, with a number distribution that peaks around a redshift of 0.4. For the 10 highest significance SZE-selected cluster candidates, all of which are optically confirmed, the mass threshold is 1 x 10(15) M-circle dot and the redshift range is 0.167-1.066. Archival observations from Chandra, XMM-Newton, and ROSAT provide X-ray luminosities and temperatures that are broadly consistent with this mass threshold. Our optical follow-up procedure also allowed us to assess the purity of the ACT cluster sample. Eighty (one hundred) percent of the 148 GHz candidates with signal-to-noise ratios greater than 5.1 (5.7) are confirmed as massive clusters. The reported sample represents one of the largest SZE-selected sample of massive clusters over all redshifts within a cosmologically significant survey volume, which will enable cosmological studies as well as future studies on the evolution, morphology, and stellar populations in the most massive clusters in the universe.
- ItemThe LABOCA/ACT survey of clusters at all redshifts: multiwavelength analysis of background submillimeter galaxies(2018) Aguirre Aparicio, Paula; Lindner, Robert R.; Baker, Andrew J.; Bond, J. Richard; Dunner Planella, Rolando; Galaz, Gaspar; Gallardo, Patricio; Hilton, Matt; Hughes, John P.; Infante Lira, Leopoldo; Lima, Marcos; Menten, Karl M.; Sievers, Jonathan; Weiss, Axel; Wollack, Edward J.; Aguirre Aparicio, Paula; Lindner, Robert R.; Baker, Andrew J.; Bond, J. Richard; Dunner Planella, Rolando; Galaz, Gaspar; Gallardo, Patricio; Hilton, Matt; Hughes, John P.; Infante Lira, Leopoldo; Lima, Marcos; Menten, Karl M.; Sievers, Jonathan; Weiss, Axel; Wollack, Edward J.