Browsing by Author "Márquez, I."

Now showing 1 - 4 of 4
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    AT 2021hdr: A candidate tidal disruption of a gas cloud by a binary super massive black hole system
    (EDP Sciences, 2024) Hernández-García, L.; Muñoz-Arancibia, A. M.; Lira, P.; Bruni, G.; Cuadra, J.; Arévalo, P.; Sánchez-Sáez, P.; Bernal, S.; Bauer, Franz Erik; Catelan, Márcio; Panessa, F.; Pávez-Herrera, M.; Ricci, C.; Reyes-Jainaga, I.; Ailawadhi, B.; Chavushyan, V.; Dastidar, R.; Deconto-Machado, A.; Forster, F.; Gangopadhyay, A.; García-Pérez, A.; Márquez, I.; Masegosa, J.; Misra, K.; Patiño-Alvarez, V. M.; Puig-Subira, M.; Rodi, J.; Singh, M.
    With a growing number of facilities able to monitor the entire sky and produce light curves with a cadence of days, in recent years there has been an increased rate of detection of sources whose variability deviates from standard behavior, revealing a variety of exotic nuclear transients. The aim of the present study is to disentangle the nature of the transient AT 2021hdr, whose optical light curve used to be consistent with a classic Seyfert 1 nucleus, which was also confirmed by its optical spectrum and high-energy properties. From late 2021, AT 2021hdr started to present sudden brightening episodes in the form of oscillating peaks in the Zwicky Transient Facility (ZTF) alert stream, and the same shape is observed in X-rays and UV from Swift data. The oscillations occur every ≈60-90 days with amplitudes of ≈0.2 mag in the g and r bands. Very Long Baseline Array (VLBA) observations show no radio emission at milliarcseconds scale. It is argued that these findings are inconsistent with a standard tidal disruption event (TDE), a binary supermassive black hole (BSMBH), or a changing-look active galactic nucleus (AGN); neither does this object resemble previous observed AGN flares, and disk or jet instabilities are an unlikely scenario. Here, we propose that the behavior of AT 2021hdr might be due to the tidal disruption of a gas cloud by a BSMBH. In this scenario, we estimate that the putative binary has a separation of ≈0.83 mpc and would merge in ≈7 × 104 years. This galaxy is located at 9 kpc from a companion galaxy, and in this work we report this merger for the first time. The oscillations are not related to the companion galaxy.
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    The impact from survey depth and resolution on the morphological classification of galaxies
    (2015) Povic, M.; Márquez, I.; Masegosa, J.; Perea, J.; Del Olmo, A.; Simpson, C.; Aguerri, J.; Ascaso, B.; Jiménez, Y.; Infante Lira, Leopoldo
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    THE. ALHAMBRA. SURVEY. : EVOLUTION. OF. GALAXY. SPECTRAL. SEGREGATION
    (2016) Hurtado Gil, L.; Arnalte Mur, P.; Martínez, V. J.; Fernández Soto, A.; Stefanon, M.; Ascaso, B.; López Sanjuán, C.; Márquez, I.; Povic, M.; Infante Lira, Leopoldo
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    Two-dimensional multi-component photometric decomposition of CALIFA galaxies
    (2017) Méndez Abreu, J.; Ruiz Lara, T.; Sánchez Menguiano, L.; De Lorenzo Cáceres, A.; Costantin, L.; Catalán Torrecilla, C.; Florido, E.; Aguerri, J. A. L.; Bland Hawthorn, J.; Sánchez Blazquez, Patricia; Corsini, E. M.; Dettmar, R. J.; Galbany, L.; García Benito, R.; Marino, R. A.; Márquez, I.; Ortega Minakata, R. A.; Papaderos, P.; Sánchez, S. F.; Spekkens, K.