Browsing by Author "Lopez-Caraballo, Carlos H."

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    GMRT 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, Edward
    We 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.
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    The 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.