The population of very low-mass satellites beyond the Local Group
Abstract
The number and structural properties of the lowest-massgalaxies (less than ~10^6 Msun) that accompany galaxies like the Milky Way arekey to ruling out different dark matter models. However, this populationremains hidden beyond the Local Group due to its low brightness. In this study,we present the results of the LIGHTS survey in this area. With a currentsurface brightness limit of 31 mag/arcsec², LIGTHS is the deepest survey ofMilky Way–like galaxies beyond the local group to date (typical distance ~15Mpc). We will present the current detection limits and discuss what to expectfrom the next generation of ultra-deep surveys, such as LSST or Arrakhis.
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The population of very low-mass satellites beyond the Local Group Minh Ngoc Le Instituto de Astrofísica de Canarias (IAC) FUNDING BY THE EUROPEAN UNION (MSCA EDUCADO, GA 101119830). Ignacio Trujillo (IAC), Johan Knapen (IAC), Michael Wilkinson (RUG), Reynier Peletier (RUG), Zeljko Ivezic (DiRAC)
The population of very low-mass satellites beyond the Local Group
The population of very low-mass satellites beyond the Local Group low surface brightness
Image credit: Trujillo+21 1.How “low’’ is Low Surface Brightness (LSB)? The Sloan Digital Sky Survey (SDSS): large sky survey, μ ∼ 26.5 mag arcsec *, ~ 1 min, D = 2.5m V−2 SDSS LBT LBT (LIGHTS surveys): μ ∼ 31 mag arcsec *, 1.5h, D = 8.4 m V−2 NGC1052-DF1 galaxy with ~ 26.7 mag arcsec−2 Low Surface Brightness: surface brightness is not detected by SDSS surveys (*3 , box of 10"x10")
The number of faint/low mass galaxies is key to rule out different dark matter models. 2. Why do we study LSBs (Newton+21) Luminosity function of satellites around a simulated MW-like galaxy
2. Why do we study LSBs (Sánchez Almeida+24) The structure of faint/low mass galaxies is key to rule out different dark matter models. CDM: DM halos are cuspy (NFW), with baryon feedback → core For low mass galaxies → negligible baryon feedback → expected DM halos remain cuspy Study the structure of low mass galaxies → DM profiles → ruling DM models.
2. Why LSBs remain hidden? Sources detected in the field of NGC4307 with 2.5h on LBT
2. Why LSBs remain hidden? Carina III Pictor I Draco Sculptor Fornax Sample of ~55 MW satellite galaxies (Simon+19), cyan dots, put beyond Local Group (15 Mpc)
2. Why LSBs remain hidden? Carina III Pictor I Draco Sculptor Fornax Sample of ~55 MW satellite galaxies (Simon+19), cyan dots, put beyond Local Group (15 Mpc)
3. Searching for LSBs with LIGHTS
Create a sample of MW satellite-like galaxies (g-band mag, r_e) The other properties of the galaxy (position angle, Sersic index,...) are fixed. 3. Searching for LSBs with LIGHTS
400 realizations (10 galaxies each) Simulated galaxies (cyan) are placed away from other galaxies, bright sources, and image edges. Simulations using Galsim (Rowe+25) 3. Searching for LSBs with LIGHTS
Segmentation (MTO2) 3. Searching for LSBs with LIGHTS
4. How well can LIGHTS detect LSBs Detection: sources detected and not in original catalog (Le+25, in prep)
Accuracy: detection and and 4. How well can LIGHTS detect LSBs (Le+25, in prep)
Accuracy: detection and and 4. How well can LIGHTS detect LSBs Up to 50% of simulated galaxies at g = 27.5 [mag] are recovered in LIGHTS. (Le+25, in prep)
4. How well can LIGHTS detect LSBs Draco Sculptor Fornax Analog of Draco g = 22.3 [mag] 2"
4. How well can LIGHTS detect LSBs Pictor I Draco Sculptor Fornax Analog of Pictor I g = 27.5 [mag] 2"
4. How well can LIGHTS detect LSBs Carina III Pictor I Draco Sculptor Fornax Analog of Carina III g = 28.8 [mag] 2"