BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Transients on the Edge DTSTART:20260115T143000Z DTEND:20260115T160000Z DTSTAMP:20260628T190744Z UID:72642632-fc25-441d-bab0-e1427aabb72e SEQUENCE:1 CREATED:20260113T132545Z DESCRIPTION: Astrophysical transients — temporary fireworks illuminating the Universe — are unique tools that allow us to study physics on all s cales. This year\, two revolutionary feats of engineering will allow the s tudy of transients like never before. The Vera Rubin Observatory'\;s L egacy Survey of Space and Time (LSST) will soon be discovering hundreds of thousands of transients per year. To provide deeper insights on this gian t dataset\, the Time Domain Extragalactic Survey (TiDES) will classify ove r 30\,000 transients and obtain spectra of a further 100\,000\, mapping tr ansient parameter space in exquisite detail. I am interested in two distin ct regions of this parameter space. Type Ia supernovae are the explosions of white dwarf stars and\, due to their very uniform peak luminosities\, h ave led the effort to measure distances and infer cosmological parameters for the last 30 years. With modern surveys achieving increasingly precise measurements of dark energy\, subtle correlations between the supernovae a nd properties of their host galaxies threaten to limit this progress. I wi ll show how LSST and TiDES will address and overcome these issues. Secondl y\, I will discuss a relatively new\, puzzling type of transient: extremel y long lived\, luminous flares from the centres of galaxies. These ambiguo us nuclear transients (ANTs) are too bright and have different spectra fro m regular tidal disruptions of stars by massive black holes\, but are equa lly unable to be explained by a standard steady-state active galactic nucl eus. LSST will increase the sample of ANTs by an order of magnitude. I wil l highlight the excitement and challenges faced trying to understand what they are and their important role in galaxy evolution. LAST-MODIFIED:20260113T132545Z LOCATION:DF Seminar Room (2-8.3)\, 2nd floor of Physics Building URL:http://df.vps.tecnico.ulisboa.pt/en/events/transients-on-the-edge/ X-ALT-DESC;FMTTYPE=text/html:

Astrophysical tran sients — temporary fireworks illuminating the Universe — are unique to ols that allow us to study physics on all scales. This year\, two revoluti onary feats of engineering will allow the study of transients like never b efore. The Vera Rubin Observatory'\;s Legacy Survey of Space and Time (LSST) will soon be discovering hundreds of thousands of transients per ye ar.

To provide deeper insights on this giant dataset\, the Time Domain Extragalactic Survey (TiDES) will classify over 30\,000 transients and obtain spectra of a further 100\,000\, mapping transient parameter spa ce in exquisite detail. I am interested in two distinct regions of this pa rameter space. Type Ia supernovae are the explosions of white dwarf stars and\, due to their very uniform peak luminosities\, have led the effort to measure distances and infer cosmological parameters for the last 30 years .

With modern surveys achieving increasingly precise measurement s of dark energy\, subtle correlations between the supernovae and properti es of their host galaxies threaten to limit this progress. I will show how LSST and TiDES will address and overcome these issues. Secondly\, I will discuss a relatively new\, puzzling type of transient: extremely long live d\, luminous flares from the centres of galaxies. These ambiguous nuclear transients (ANTs) are too bright and have different spectra from regular t idal disruptions of stars by massive black holes\, but are equally unable to be explained by a standard steady-state active galactic nucleus. LSST w ill increase the sample of ANTs by an order of magnitude. I will highlight the excitement and challenges faced trying to understand what they are an d their important role in galaxy evolution.

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