Ultra-deep imaging of M33: exploring its stellar halo with broad band imaging for the first time

Sharbaf, Zahra; Akhlaghi, Mohammad; Golini, Giulia; Trujillo, Ignacio; Infante-Sainz, Raul; Altafi, Hamed; Khosroshahi, Habib; Saremi, Elham; Molaeinezhad, Alireza; Fatemi, Surena; Haddad, Mohammad Ali
Referencia bibliográfica

EAS2024

Advertised on:
7
2024
Número de autores
11
Número de autores del IAC
3
Número de citas
0
Número de citas referidas
0
Descripción
The star counting technique by the PAndAS survey reveals that M33 is undergoing a tidal interaction with its massive neighbor, M31. Due to this interaction, the stellar halo of M33 shows faint tidal features. These features are only visible at extremely low surface brightness levels (i.e. >30 mag/arcsec^2). For this reason, M33 is a perfect test bed for comparing ultra-deep broad-band imaging with star counting techniques to characterize the faintest surface brightness stellar emission. We present the first attempt at exploring the stellar halo of M33 using ultra-deep broad-band imaging. Our experiment is conducted using the Iranian National Observatory Lens Array (INOLA). INOLA's field-of-view is 1.9 by 2.5 degrees, with a pixel size of 2.8 arcsec/pixel, easily covering M33 and its halo in one single exposure. Low surface brightness imaging needs accurate observing strategies and data reduction procedures. We will address a detailed description of all the technical challenges we have dealt with, including the construction of a very extended non-parametric point spread function (PSF) out to a radius of 45 arcminutes, scattered light removal of 4400 stars, and background subtraction. The technological challenges are essential points for upcoming deep surveys, such as the LSST. The results obtained in this work are in excellent agreement with the star counting technique, which opens up the possibility of studying the stellar halo of distant galaxies where the stellar populations can not be resolved (i.e. >16 Mpc) on solid ground.