48 citations · 278 across the 32 of their papers we have counts for
32 papers
Spatially resolved optical and mid-infrared spectroscopy of SDSS1335+0728: implications for the origin of the Ansky event
P. Sánchez-Sáez, M. Masterson, L. Hernández-García +25
The galaxy SDSS1335+0728 brightened abruptly in December 2019 (the Ansky event) and has since been confirmed as the host of extreme X-ray quasi-periodic eruptions (QPEs) of debated…
A Meta-Learning Framework for Multitask Reverberation Mapping in Active Galactic Nuclei
Aman N. Raju, Andjelka B. Kovačević, Dragana Ilić +8
The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) is expected to observe active galactic nuclei (AGN) at sky densities of approximately 1000-4000 per sq. deg, en…
Spectral Handling and Estimation of AGN Parameters (SHEAP), The first AGN fitting GPU-based code
F. Ávila-Vera, P. Sánchez-Sáez, V. Motta +1
In the coming years, the number of discovered active galactic nuclei (AGN) is expected to increase significantly due to upcoming spectroscopic surveys. This growth will challenge c…
Fast and Flexible Characterisation of Astronomical Light Curves Using Multi-Time Attention
Yash Gondhalekar, Anais Möller, Paula Sánchez-Sáez
We present an unsupervised, data-driven framework for rapid characterisation of astronomical photometric time series using a Multi-Time Attention Network. The model learns time-awa…
Evidence for a Delayed UV Counterpart to X-ray Quasi-periodic Eruptions in Ansky
Hengxiao Guo, Zhen Yan, Ya-Ping Li +15
X-ray quasi-periodic eruptions (QPEs) represent a novel population of extreme, repeating nuclear transients whose physical origins remain debated. A defining characteristic of QPEs…
A positive period derivative in the quasi-periodic eruptions of ZTF19acnskyy
Joheen Chakraborty, Saul A. Rappaport, Riccardo Arcodia +9
We report the first direct measurement of the period derivative in a quasi-periodic eruption (QPE), finding a smoothly increasing period with $\dot{P}\approx (1.7\pm 0.02)\times10^…
Scavenger hunt: Selection of obscured active galactic nuclei combining multiband optical variability and colors
Demetra De Cicco, Stefano Cavuoti, Maurizio Paolillo +3
As wide-field optical surveys such as Vera Rubin Observatory's Legacy Survey of Space and Time (LSST) begin operations, time-domain astronomy is facing a data revolution, paving th…
The evolution of obscured AGN across cosmic time -- A large quasar survey for the 2040s
Tanya Urrutia, Darshan Kakkad, Paula Sánchez-Sáez +21
We propose a large quasar demographic optical multi-object spectroscopic (MOS) survey targeting over 50 million AGN candidates up to the highest redshifts possible in the optical (…
Lost and Found - A gallery of overlooked optical nuclear transients from the ZTF archive
E. Quintin, E. Russeil, M. Llamas Lanza +12
Tidal disruption events (TDEs) correspond to the destruction of a star by the tidal forces around a black hole, leading to outbursts which can last from months to years. These tran…
Unlocking AGN Variability with Custom ZTF Photometry for High-Fidelity Light Curves and Robust Selection
P. Arévalo, P. Sánchez-Sáez, B. Sotomayor +3
(Abridged)We explore the potential of optical variability selection methods to identify AGN, including those challenging to detect with conventional techniques. Using the unprecede…
NICER observations reveal doubled timescales in Ansky's quasi-periodic eruptions (QPEs)
L. Hernández-García, P. Sánchez-Sáez, J. Chakraborty +11
Quasi-periodic eruptions (QPEs) are recurring X-ray bursts originating from the vicinity of supermassive black holes, but their driving mechanisms remain under debate. This study a…
Astrophotometric search for massive stars in the Milky way. Confronting Random Forest predictions with available spectroscopy
N. Monsalves, A. Bayo, M. Jaque Arancibia +4
Massive stars play a significant role in different branches of astronomy, from shaping the processes of star and planet formation to influencing the evolution and chemical enrichme…
A new Bowen Fluorescence Flare and Extreme Coronal Line Emitter discovered by SRG/eROSITA
Pietro Baldini, Arne Rau, Riccardo Arcodia +19
The nuclear transient eRASSt J012026.5-292727 (J012026 hereafter) was discovered in the second SRG/eROSITA all-sky survey (eRASS2). The source appeared more than one order of magni…
Navigating AGN variability with self-organizing maps
Ylenia Maruccia, Demetra De Cicco, Stefano Cavuoti +6
Context. The classification of active galactic nuclei (AGNs) is a challenge in astrophysics. Variability features extracted from light curves offer a promising avenue for distingui…
Selection of optically variable active galactic nuclei via a random forest algorithm
Demetra De Cicco, Gaetano Zazzaro, Stefano Cavuoti +5
Context. A defining characteristic of active galactic nuclei (AGN) that distinguishes them from other astronomical sources is their stochastic variability, which is observable acro…
The Intermediate-Mass Black Hole Reverberation Mapping Project: First Detection of Mid-Infrared Lags in Prototypical IMBHs in NGC 4395 and POX 52
Jingbo Sun, Hengxiao Guo, Wenwen Zuo +25
The search for robust evidence of intermediate-mass black holes (IMBHs) is crucial for understanding black hole seeding process and the formation of supermassive black holes in the…
ALeRCE light curve classifier: Tidal disruption event expansion pack
M. Pavez-Herrera, P. Sánchez-Sáez, L. Hernández-García +9
ALeRCE (Automatic Learning for the Rapid Classification of Events) processes the Zwicky Transient Facility (ZTF) alert stream in preparation for the Vera C. Rubin Observatory, clas…
AT 2021hdr: A candidate tidal disruption of a gas cloud by a binary super massive black hole system
L. Hernández-García, A. M. Muñoz-Arancibia, P. Lira +25
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…
Tuning into spatial frequency space: Satellite and space debris detection in the ZTF alert stream
J. P. Carvajal, F. E. Bauer, I. Reyes-Jainaga +6
A significant challenge in the study of transient astrophysical phenomena is the identification of bogus events, among which human-made satellites and debris in Earth orbit remain…
Application of Convolutional Neural Networks to time domain astrophysics. 2D image analysis of OGLE light curves
N. Monsalves, M. Jaque Arancibia, A. Bayo +4
In recent years the amount of publicly available astronomical data has increased exponentially, with a remarkable example being large scale multiepoch photometric surveys. This wea…
SDSS1335+0728: The awakening of a black hole
P. Sánchez-Sáez, L. Hernández-García, S. Bernal +22
The galaxy SDSS1335+0728, which had exhibited no prior optical variations during the preceding two decades, began showing significant nuclear variability in the Zwicky Transient Fa…
ATAT: Astronomical Transformer for time series And Tabular data
G. Cabrera-Vives, D. Moreno-Cartagena, N. Astorga +14
The advent of next-generation survey instruments, such as the Vera C. Rubin Observatory and its Legacy Survey of Space and Time (LSST), is opening a window for new research in time…
A Newborn AGN in a Starforming Galaxy
P. Arévalo, E. López-Navas, M. L. Martínez-Aldama +8
We report on the finding of a newborn AGN, i.e. current AGN activity in a galaxy previously classified as non-active, and characterize its evolution. Black hole ignition event cand…
Improving the selection of changing-look AGNs through multi-wavelength photometric variability
E. López-Navas, P. Sánchez-Sáez, P. Arévalo +13
We present second epoch optical spectra for 30 changing-look (CL) candidates found by searching for Type-1 optical variability in a sample of active galactic nuclei (AGNs) spectros…