arXiv subjects

Anna Pospieszalska-Surdej

Publications and source records attributed to Anna Pospieszalska-Surdej.

7 recordsLinked to original sources

arXiv2026

Demonstrating the Time-Domain Capabilities of the 4-m International Liquid Mirror Telescope: An Early Census of Transient and Variable Detections

The PyLMT transient detection pipeline has been operational since November 2023, detecting transient and variable objects in the ILMT images in almost real time. Using the image subtraction technique, nearly 3700 CCD frames have been analyzed by the automated pipeline, generating nearly 23,000 alerts for the detection of verified transient candidates and cataloged variable sources. Around 21,000 of the alerts correspond to known MPC asteroids, nearly 2000 correspond to variable stars (including eclipsing binaries, RR Lyrae, Delta Scuti, T-Tauri, etc.), 509 correspond to variable AGNs (including QSOs, Seyfert galaxies, and blazars), 21 supernova candidates, and several other interesting candidates. We provide a concise overview of the detections and their significance, emphasizing the surveys potential contributions to a broad class of astrophysical and scientific cases. A transient detection dashboard called DART was developed using Streamlit to visualize and categorize candidates based on PyLMT and SIMBAD classifications. It includes cone-search functionality and displays key metadata, offering an intuitive interface that is publicly accessible. Our results demonstrate the viability of liquid mirror telescopes such as the ILMT for time-domain astronomy, emphasizing the important role that small-field survey facilities can play in systematic transient science programs.

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arXiv2026

Performance of the 4-m International Liquid Mirror Telescope tested in two fields at high and low ecliptic and galactic latitudes

The 4-m International Liquid Mirror Telescope (ILMT) offers a unique opportunity to detect transients in a narrow strip of sky. We explore ILMT's potential to detect astrometric and photometric transients at various ecliptic and galactic latitudes. We inspected CCD frames observed at both low and high ecliptic and galactic latitudes during the commissioning phase and the November 2023 - May 2024 observation cycle, respectively. We analysed these images using both visual inspection and the ILMT's transient detection and candidate classification pipeline. In the low ecliptic and galactic latitude field, we detected more than 500 transient candidates. We cross-matched these with the Minor Planet Checker (MPC) database, identifying 504 catalogued asteroids, all with predicted V-magnitudes brighter than 24 mag, representing a total of 152 distinct asteroids. We performed the same steps on the high ecliptic and galactic latitude field, detecting 30 MPC-catalogued asteroids, and one newly discovered photometric transient, named AT 2024fxn. We present the positions, trajectories, and magnitudes of the detected asteroids observed in the SDSS g', r', and i' spectral bands and compare results from both fields. We explore the lightcurve of AT 2024fxn, which shows partial compatibility with a supernova (SN) hypothesis, while the data invites further insights.

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arXiv2025

The 4m International Liquid Mirror Telescope: Construction, operation, and science

The International Liquid Mirror Telescope (ILMT) project was motivated by the need for an inexpensive 4 metre diameter optical telescope that could be devoted entirely to astronomical surveys. Its scientific programmes include the detection and study of transients, variable objects, asteroids, comets, space debris and low surface brightness galaxies. To this end, a collaboration was formed between the Institute of Astrophysics and Geophysics (Liège University, Belgium), several Canadian universities (University of British Columbia, Laval University, University of Montreal, University of Toronto, York University, University of Victoria) and the Aryabhatta Research Institute of Observational Sciences (ARIES, India). After several years of design work in Belgium and construction in India on the ARIES Devasthal site, the telescope saw its first light on 29 April 2022. Its commissioning phase lasted from May 2022 until June 2023 (beginning of the monsoon). The ILMT was inaugurated on 21 March 2023 and has been in regular operation since October 2023. The telescope continuously observes the sky passing at the zenith using the SDSS g', r', and i' filters. This paper describes the ILMT, its operation, performance and shows some initial results.

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arXiv2023

Detection and Identification of Asteroids with the 4-m ILMT

A very unique strength of the Devasthal Observatory is its capability of detecting optical transients with the 4-m International Liquid Mirror Telescope (ILMT) and to rapidly follow them up using the 1.3-m Devasthal Fast Optical Telescope (DFOT) and/or the 3.6-m Devasthal Optical Telescope (DOT), installed right next to it. In this context, we have inspected 20 fields observed during 9 consecutive nights in October-November 2022 during the first commissioning phase of the ILMT. Each of these fields has an angular extent of $22^\prime$ in declination by $9 \times 22^\prime$ in right ascension. Combining both a visual search for optical transients and an automatic search for these using an image subtraction technique (see the ILMT poster paper by Pranshu et al.), we report a total of 232 significant transient candidates. After consulting the Minor Planet Center database of asteroids, we could identify among these 219 positions of known asteroids brighter than $V=22$. These correspond to the confirmed positions of 78 distinct known asteroids. Analysis of the remaining CCD frames covering 19 more fields (out of 20) should lead to an impressive number of asteroids observed in only 9 nights. The conclusion is that in order to detect and characterize new supernovae, micro-lensing events, highly variable stars, multiply imaged quasars, etc. among the ILMT optical transients, we shall first have to identify all known and new asteroids. Thanks to its large diameter and short focal length (f/D $\sim$ 2.4), the ILMT turns out to be an excellent asteroid hunter.

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arXiv2023

The 4m International Liquid Mirror Telescope project

The International Liquid Mirror Telescope (ILMT) project is a scientific collaboration in observational astrophysics between the Li{è}ge Institute of Astrophysics and Geophysics (Li{è}ge University, Belgium), the Aryabatta Research Institute of observational sciencES (ARIES, Nainital, India) and several Canadian universities (British Columbia, Laval, Montr{é}al, Toronto, Victoria and York). Meanwhile, several other institutes have joined the project: the Royal Observatory of Belgium, the National University of Uzbekistan and the Ulugh Beg Astronomical Institute (Uzbekistan) as well as the Pozna{ń} Observatory (Poland). The Li{è}ge company AMOS (Advanced Mechanical and Optical Systems) has fabricated the telescope structure that has been erected on the ARIES site in Devasthal (Uttarakhand, India). It is the first liquid mirror telescope being dedicated to astronomical observations. First light was obtained on 29 April 2022 and commissioning is being conducted at the present time. In this short article, we describe and illustrate the main components of the ILMT. We also highlight the ILMT papers presented during the third BINA workshop, which discuss various aspects of the ILMT science programs.

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arXiv2023

Observation of mulitply imaged quasars with the 4-m ILMT

Gravitationally lensed quasars (GLQs) are known to potentially provide an independent way of determining the value of the Hubble-Lemaître parameter $H_{0}$, to probe the dark matter content of lensing galaxies and to resolve tiny structures in distant active galactic nuclei. That is why multiply imaged quasars are one of the main drivers for a photometric monitoring with the 4-m International Liquid Mirror Telescope (ILMT). We would like to answer the following questions -- how many multiply imaged quasars should we be able to detect with the ILMT? And how to derive accurate magnitudes of the GLQ images? Our estimation of the possible number of multiply imaged quasars is $15$, although optimistic forecasts predict up to $50$ of them. We propose to use the adaptive PSF fitting method for accurate flux measurements of the lensed images. During preliminary observations in spring 2022 we were able to detect the quadruply imaged quasar - SDSS J1251+2935 in the $\it{i}$ and $\it{r}$ spectral bands.

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arXiv2023

The 4m International Liquid Mirror Telescope: a brief history and some preliminary scientific results

The present article is based upon an invited talk delivered at the occasion of the inauguration of the 4m International Liquid Mirror Telescope (ILMT) which took place in Devasthal (ARIES, Uttarakhand, India) on 21st of March 2023. We present hereafter a short history of the liquid mirror telescopes and in particular of the 4m ILMT which is the first liquid mirror telescope entirely dedicated to astrophysical observations. We discuss a few preliminary scientific results and illustrate some direct CCD images taken during the first commissioning phase of the telescope. We invite the reader to refer to the series of ILMT poster papers published in these same proceedings of the BINA3 workshop for more details about the instrument, operation, first observations, performance and scientific results.

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