Almost all astronomical transients are hosted by a galaxy. Hostless transients are rare and have been associated with events that probe the extremes of physical mechanisms. Early identification based on their hostless characteristics would allow rapid follow-up and consequently better datasets for modelling and interpretation. Most apparently hostless events are not in fact hostless but their...
Active Galactic Nuclei (AGN) are variable sources, and analyzing the time delay of the strong broad optical emission lines relative to the underlying continuum serves as a crucial tool to investigate this important trait. This method aids in measuring black hole masses, and deciphering the structure of the Broad Line Region (BLR) responsible for these emission lines, which can be extended to...
Strong lensing time-delays provide an independent method for measuring $H_0$ and probing cosmology. Although multiply imaged transients are very rare, ongoing and upcoming projects in wide-field surveys are expected to discover thousands of such systems, especially in the Vera Rubin Observatory Legacy Survey of Space and Time (LSST) survey. As a preparation for this unprecedented amount of...
Thanks to the large sky coverage and the high cadence, the Rubin Observatory Legacy Survey of Space and Time (LSST) will reveal on the order of 100,000 strongly lensed galaxy-scale systems and revolutionize transient studies. With dedicated neural network classifiers trained on realistic mock images, we will be able to analyze all LSST images, and detect these lens candidates. By...
ALeRCE (http://alerce.science/) is an alert annotation and classification system led by an interdisciplinary and interinstitutional group of scientists based in Chile. ALeRCE focuses primarily on transients, variable stars, and stochastic sources. Thanks to its state-of-the-art machine learning models, ALeRCE has become the third-leading contributor in reporting candidates to the Transient...
Kilonovae are a class of astronomical transients observed as counterparts to mergers of compact binary systems, such as a binary neutron star (BNS) or black hole-neutron star (BHNS) inspirals. They serve as probes for heavy-element nucleosynthesis in astrophysical environments, while together with gravitational wave emission constraining the distance to the merger itself, they can place...
Time-domain surveys, such as DECam, ZTF, and the forthcoming Vera Rubin Telescope, open new possibilities for discovering explosive transients in our Universe. Optical flares, in particular, have been widely considered as potential counterparts to gravitational waves measured by the LIGO-Virgo-KAGRA Collaboration (LVK). While binary black hole (BBH) mergers dominate the population of...
In astronomy, transients are a source of new discoveries about the universe. Kilonovae are a type of transient resulting from the collision between neutron stars or between a neutron star and a black hole in compact binary systems, and currently, it is the only object with electromagnetic and gravitational wave counterparts (GW170817). As we navigate in the Big Data era, and expect the...
The discovery of the accelerating expansion of the universe has led to increasing interest in probing the nature of dark energy. As very bright standardizable candles, type Ia supernovae (SNe Ia) are used to measure precise distances on cosmological scales and thus have been instrumental to this effort. Building a robust dataset of SNe Ia across a wide range of redshifts will allow for the...
Pre-polars are detached binary systems composed by a magnetic white dwarf (WD) accreting matter by the capture of the stellar wind of a cool donor, usually a late-type main sequence star. These systems can be the progenitors of polars, which is a subclass of magnetic cataclysmic variable consisting of a Roche Lobe filling low-mass companion star and a strongly magnetized WD. Nowadays the...
Red supergiants (RSGs) stars are a stage of the life cycle of a massive star, with mass greater than 8 times the mass of the Sun. At the end of their lives, these stars either explode as supernovae or collapse directly into black holes. Having an efficient alert system allows us to infer the fundamental properties of the supernova progenitor star, that are contained mostly in the early phases...
We present a light curve fitter for type Ia Supernovae dubbed Pure Expansion Template for Supernovae (PETS). The model consists of an expansion of its rest-frame flux based on the well-known Spectral Adaptive Light Curve Template 2 (SALT2). We generate the expansion components by performing Principal Component Analysis (PCA) and Factor Analysis (FA) onto a representative training set. Then, we...
Differential Chromatic Refraction (DCR) is caused by the wavelength dependence of our atmosphere's refractive index that shifts the apparent positions of stars and galaxies and distorts their shapes depending on their spectral energy distribution (SED). While this effect is typically mitigated and corrected for in imaging observations, we investigate how DCR can instead be used to our...
The identification and characterization of exoplanets have surpassed 5000 celestial bodies, by using various techniques, such as the transit method, which depends on the periodic transits caused by the planet passing in front of the star, and the radial velocity method which relies on the oscillations in absorption line positions in stellar spectra. Each technique has specific advantages; the...
Abstract The Observatory Control System (OCS), a comprehensive software package developed by Las Cumbres Observatory (LCO), helps automate a number of important steps related to the robotic operations of an optical observatory. For example, managing the configuration database of telescopes, instruments, and components, observation submission and scheduling, handling various alerts, etc. The...
