Examinando por Autor "Damke, G."

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    LIGHT CURVES OF 213 TYPE Ia SUPERNOVAE FROM THE ESSENCE SURVEY
    (IOP PUBLISHING, 2016) Narayan, G.; Rest, A.; Tucker, B. E.; Foley, R. J.; Wood-Vasey, W. M.; Challis, P.; Stubbs, C.; Kirshner, R. P.; Aguilera, C.; Becker, A. C.; Blondin, S.; Clocchiatti, A.; Covarrubias, R.; Damke, G.; Davis, T. M.; Filippenko, A. V.; Ganeshalingam, M.; Garg, A.; Garnavich, P. M.; Hicken, M.; Jha, S. W.; Krisciunas, K.; Leibundgut, B.; Li, W.; Matheson, T.; Miknaitis, G.; Pignata, G.; Prieto, J. L.; Riess, A. G.; Schmidt, B. P.; Silverman, J. M.; Smith, R. C.; Sollerman, J.; Spyromilio, J.; Suntzeff, N. B.; Tonry, J. L.; Zenteno, A.
    The ESSENCE survey discovered 213 Type Ia supernovae at redshifts 0.1 < z < 0.81 between 2002 and 2008. We present their R- and I-band photometry, measured from images obtained using the MOSAIC II camera at the CTIO Blanco, along with rapid-response spectroscopy for each object. We use our spectroscopic follow-up observations to determine an accurate, quantitative classification, and precise redshift. Through an extensive calibration program we have improved the precision of the CTIO Blanco natural photometric system. We use several empirical metrics to measure our internal photometric consistency and our absolute calibration of the survey. We assess the effect of various potential sources of systematic bias on our measured fluxes, and estimate the dominant term in the systematic error budget from the photometric calibration on our absolute fluxes is similar to 1%.
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    The First Galaxy Cluster Discovered by the VISTA Variables in the Vía Láctea Survey
    (Astrophysical Journal, 2019-03-20) Baravalle, L. D.; Nilo Castellón, J. L.; Alonso, M. V.; Díaz Tello, J.; Damke, G.; Valotto, C.; Cuevas Larenas, H.; Sánchez, B.; de los Ríos, M.; Minniti, D.; Domínguez, M.; Gurovich, S.; Barbá, R.; Soto, M.; Milla Castro, F.
    We report the first confirmed detection of the galaxy cluster VVV-J144321-611754 at very low latitudes (l = 315.°836, b = -1.°650) located in the tile d015 of the VISTA Variables in the Vía Láctea (VVV) survey. We defined the region of 30 ×30 arcmin 2 centered in the brightest galaxy finding 25 galaxies. For these objects, extinction-corrected median colors of (H-K s ) = 0.34 ± 0.05 mag, (J-H) = 0.57 ± 0.08 mag, and (J-K s ) = 0.87 ± 0.06 mag; R 1/2 = 1.59 ± 0.″16; C = 3.01 ± 0.08; and Sérsic index n = 4.63 ± 0.39 were estimated. They were visually confirmed showing characteristics of early-type galaxies in the near-IR images. An automatic clustering analysis performed in the whole tile found that the concentration of galaxies VVV-J144321-611754 is a real, compact concentration of early-type galaxies. Assuming a typical galaxy cluster with low X-ray luminosity, the photometric redshift of the brightest galaxy is z = 0.196 ± 0.025. Follow-up near-IR spectroscopy with FLAMINGOS-2 at the Gemini-South telescope revealed that the two brighter cluster galaxies have typical spectra of early-type galaxies and the estimated redshift for the brightest galaxy VVV-J144321.06-611753.9 is z = 0.234 ± 0.022 and that for VVV-J144319.02-611746.1 is z = 0.232 ± 0.019. Finally, these galaxies clearly follow the cluster red sequence in the rest-frame near-IR color-magnitude diagram with a slope similar to a galaxy cluster at a redshift of 0.2. These results are consistent with the presence of a bona fide galaxy cluster beyond the Milky Way disk.