Browsing by Author "Arévalo, P."
Now showing 1 - 14 of 14
Results Per Page
Sort Options
- ItemA hard X-ray view of luminous and ultra-luminous infrared galaxies in GOALS - I. AGN obscuration along the merger sequence(2021) Ricci, C.; Privon, G. C.; Pfeifle, R. W.; Armus, L.; Iwasawa, K.; Torres-Albà, N.; Satyapal, S.; Bauer, F. E.; Treister, E.; Ho, L. C.; Aalto, S.; Arévalo, P.; Barcos-Muñoz, L.; Charmandaris, V.; Diaz-Santos, T.; Evans, A. S.; Gao, T.; Inami, H.; Koss, M. J.; Lansbury, G.; Linden, S. T.; Medling, A.; Sanders, D. B.; Song, Y.; Stern, D.; U, V.; Ueda, Y.; Yamada, S.The merger of two or more galaxies can enhance the inflow of material from galactic scales into the close environments of active galactic nuclei (AGNs), obscuring and feeding the supermassive black hole (SMBH). Both recent simulations and observations of AGN in mergers have confirmed that mergers are related to strong nuclear obscuration. However, it is still unclear how AGN obscuration evolves in the last phases of the merger process. We study a sample of 60 luminous and ultra-luminous IR galaxies (U/LIRGs) from the GOALS sample observed by NuSTAR. We find that the fraction of AGNs that are Compton thick (CT;N-H >= 10(24)cm(-2) ) peaks at at a late merger stage, prior to coalescence, when the nuclei have projected separations (d(sep)) of 0.4-6 kpc. A similar peak is also observed in the median N-H [[(1.6 +/- 0.5) x 10(24) cm(-2)].]. The vast majority (85(-9)(+7) per cent)) of the AGNs in the final merger stages (d(sep) less than or similar to 10 kpc) are heavily obscured (N-H = 10(23) cm(-2)), and the median N-H of the accreting SMBHs in our sample is systematically higher than that of local hard X-ray-selected AGN, regardless of the merger stage. This implies that these objects have very obscured nuclear environments, with the gas almost completely covering the AGN in late mergers. CT AGNs tend to have systematically higher absorption-corrected X-ray luminosities than less obscured sources. This could either be due to an evolutionary effect, with more obscured sources accreting more rapidly because they have more gas available in their surroundings, or to a selection bias. The latter scenario would imply that we are still missing a large fraction of heavily obscured, lower luminosity (L2-10 less than or similar to 10(43) erg s(-1)) AGNs in U/LIRGs.
- ItemA precessing and nutating jet in OJ287(2020) Britzen, S.; Fendt, C.; Witzel, G.; Qian S., J.; Pashchenko, I. N.; Kurtanidze, O.; Zajacek, M.; Martinez, G.; Karas, V.; Cuadra, Jorge; Aller, M.; Aller, H.; Eckart, A.; Nilsson, K.; Arévalo, P.; Subroweit, M.; Witzel, A.
- ItemAlert Classification for the ALeRCE Broker System: The Light Curve Classifier(2021) Sánchez-Sáez, P.; Reyes, I.; Valenzuela, C.; Förster, F.; Eyheramendy, S.; Elorrieta, F.; Bauer, F. E.; Cabrera-Vives, G.; Estévez, P. A.; Catelan, Márcio; Pignata, G.; Huijse, P.; De Cicco, D.; Arévalo, P.; Carrasco-Davis, R.; Abril, J.; Kurtev, R.; Borissova, J.; Arredondo, J.; Castillo-Navarrete, E.; Rodríguez, D.; Ruz-Mieres, D.; Moya, A.; Sabatini-Gacitúa, L.; Sepúlveda-Cobo, C.; Camacho-Iñiguez, E.
- ItemNuStar observations of the compton-thick active galactic nucleus and ultraluminous X-Ray source candidate in NGC 5643(2015) Annuar, A.; Gandhi, P.; Alexander, D.; Lansbury, G.; Arévalo, P.; Ballantyne, D.; Balokovic, M.; Boggs, S.; Brandt, W.; Brightman, M.; Christensen, F.; Craig, W.; Del Moro, A.; Hailey, C.; Harrison, F.; Bauer, Franz Erik
- ItemNuStar spectroscopy of multiI-component X-Ray reflection from NGC 1068(2015) Bauer, Franz Erik; Arévalo, P.; Walton, D.; Koss, M.; Puccetti, S.; Gandhi, P.; Stern, D.; Alexander, D.; Balokovic, M.; Boggs, S.; Brandt, W.; Brightman, M.; Christensen, F.; Comastri, A.; Craig, W.; Del Moro, A.
- ItemPersistent and occasional: Searching for the variable population of the ZTF/4MOST sky using ZTF Data Release 11(2023) Sánchez-Sáez, P.; Arredondo, J.; Bayo, A.; Arévalo, P.; Bauer, F. E.; Cabrera-Vives, G.; Catelan, Márcio; Coppi, P.; Estévez, P. A.; Förster, F.; Hernández-García, L.; Huijse, P.; Kurtev, R.; Lira, P.; Muñoz Arancibia. A. M.; Pignata, G.
- ItemSimultaneous NuSTAR and XMM-Newton 0.5-80 keV spectroscopy of the narrow-line Seyfert 1 galaxy SWIFT J2127.4+5654(2014) Marinucci, A.; Matt, G.; Kara, E.; Miniutti, G.; Elvis, M.; Arévalo, P.; Ballantyne, D. R.; Baloković, M.; Bauer, Franz Erik; Brenneman, L.
- ItemThe Multi-Layer Variable Absorbers in NGC 1365 Revealed by XMM-Newton and NuSTAR(2015) Rivers, E.; Risaliti, G.; Walton, D. J.; Harrison, F.; Arévalo, P.; Bauer, Franz Erik; Boggs, S. E.; Brenneman, L. W.; Brightman, M.; Christensen, F. E.
- ItemThe nature of the torus in the heavily obscured AGN Markarian 3 : an X-ray study(2016) Guainazzi, M.; Risaliti, G.; Awaki, H.; Arévalo, P.; Bauer, Franz Erik; Bianchi, S.; Boggs, S.E.; Brandt, W.N.; M. Brightman, M.; Christensen, F.E.
- ItemThe NuSTAR view of reflection and absorption in NGC 7582(2015) Rivers, E.; Baloković, M.; Arévalo, P.; Bauer, Franz Erik
- ItemThe NuSTAR X-ray spectrum of the low-luminosity active galactic nucleus in NGC 7213(2015) Ursini, F.; Marinucci, A.; Matt, G.; Bianchi, S.; Tortosa, A.; Stern, D.; Arévalo, P.; Ballantyne, D.; Bauer, Franz Erik; Fabian, A.; Harrison, F.; Lohfink, A.; Reynolds, C.; Walton, D.
- ItemThe Seyfert 2 galaxy NGC 2110 : hard X-ray emission observed by NuSTAR and variability of the iron Kα line(2015) Marinucci, A.; Matt, G.; Bianchi, S.; Lu, T. N.; Arévalo, P.; Balokovic, M.; Ballantyne, D.; Bauer, Franz Erik; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Gandhi, P.; Hailey, C. J.; Harrison, F.; Puccetti, S.; Rivers, E.; Walton, D. J.; Stern, D.; Zhang, W.
- ItemTHE VARIABLE HARD X-RAY EMISSION OF NGC 4945 AS OBSERVED BY NUSTAR(2014) Arévalo, P.; Puccetti, S.; Comastri. A.; Fiore, F.; Risaliti, G.; Bauer, Franz Erik; Brandt, W.; Stern, D.
- ItemUnveiling the AGN in IC 883: discovery of a parsec-scale radio jet(2017) Romero Cañizales, Cristina; Alberdi, A.; Ricci, Claudio; Arévalo, P.; Pérez Torres, M. A.; Conway, J. E.; Beswick, R. J.; Bondi, M.; Muxlow, T. W. B.; Bauer, Franz Erik