2025MNRAS.540.1107S

Query : 2025MNRAS.540.1107S

2025MNRAS.540.1107S - Mon. Not. R. Astron. Soc., 540, 1107-1123 (2025/June-2)

The unabridged satellite luminosity function of Milky Way-like galaxies in ΛCDM: the contribution of 'orphan' satellites.

SANTOS-SANTOS I.M.E., FRENK C.S., NAVARRO J.F., COLE S. and HELLY J.

Abstract (from CDS):

We study the abundance, radial distribution, and orbits of luminous satellites in simulations of Milky Way-mass dark haloes in the $\Lambda$cold dark matter (ΛCDM) cosmology. We follow the evolution of a halo from the Aquarius project and the formation of its 'maximal' satellite population with the GALFORM semi-analytic model of galaxy formation. This population consists of all subhaloes able to form stars through efficient gas cooling before or after reionization, which effectively selects systems with peak circular velocities exceeding a critical threshold of roughly $\sim 15$-20 km s–1. The total number of luminous satellites is sensitive to the assumed redshift of reionization, but the shape of the GALFORM satellite stellar mass function is robust, peaking at the stellar mass (∼103$\mathrm{ M}_\odot$) of a halo just above the critical threshold. Subhaloes are prone to artificial disruption in the tidal field of the main halo, with the number of surviving satellites increasing with resolution. Even in the highest resolution simulation (Aq-L1, with particle mass $m_{\rm p}\sim 10^3\, \mathrm{ M}_\odot$), a substantial number of satellite subhaloes are disrupted, leaving behind 'orphan' galaxies tracked in GALFORM by the subhalo's most-bound particle before disruption. When orphans are included (and the effects of tidal stripping on stars are neglected), all simulations that adequately resolve the critical threshold yield a converged maximal satellite stellar mass function. Most orphans were accreted early, are found in the central regions of the main halo, and make up roughly half of all satellites in Aq-L1. Taking orphans into account there is no need to populate subhaloes below the critical threshold with satellites to fit the radial distribution of Milky Way satellites, as has been argued in recent work. Our model predicts that orphans dominate the ultrafaint population and that many more satellites with small apocentric radii should be detected in upcoming deep wide-field surveys.

Abstract Copyright: © 2025 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.

Journal keyword(s): galaxies: dwarf - galaxies: haloes - dark matter

Simbad objects: 68

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Number of rows : 68
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 NAME Tuc IV G 00 02.9 -60 51           ~ 90 0
2 M 31 AGN 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 13622 1
3 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 12317 1
4 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1498 4
5 NAME Cetus II G 01 17.9 -17 25           ~ 56 0
6 NAME Phoenix Dwarf Galaxy Sy1 01 51 06.3 -44 26 41   13.48 13.2 12.69   ~ 575 2
7 DELVE 2 Cl* 01 55 05 -68 15.2     17.16     ~ 20 0
8 NAME Cetus III Dwarf Galaxy LSB 02 05 19.40 -04 16 12.0           ~ 32 0
9 NAME Tri II G 02 13 17.40 +36 10 42.4           ~ 164 0
10 NAME Segue 2 G 02 19 16.0 +20 10 31     15.2     ~ 299 0
11 NAME Eri III G 02 22 45.480 -52 17 04.92           ~ 79 0
12 [LPS2017] DES J0225+0304 G? 02 25 42.40 +03 04 10.1           ~ 23 0
13 NAME Hydrus I G 02 29 33.4 -79 18 32           ~ 80 0
14 MCG-06-07-001 G 02 39 59.3 -34 26 57   9.02 7.4     ~ 1894 1
15 NAME Hor I G 02 55 31.7 -54 07 08           ~ 169 0
16 NAME Horologium II G 03 16 32.1 -50 01 05           ~ 76 0
17 NAME Reticulum II G 03 35 42.1 -54 02 57           ~ 375 0
18 NAME Eridanus II G 03 44 21.1 -43 32 00           ~ 216 0
19 NAME Reticulum III G 03 45.4 -60 27           ~ 67 0
20 NAME Pic I G 04 43 47.4 -50 16 59           ~ 58 0
21 NAME Eridanus IV G 05 05 45 -09 30.9     14.72     ~ 15 0
22 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 19090 0
23 NAME Col I G 05 31.4 -28 02           ~ 60 0
24 ESO 206-20A G 06 41 36.7 -50 57 58   22.14 11.0 19.47   ~ 1190 0
25 NAME Pic II G 06 44 43 -59 53.8           ~ 33 0
26 NAME Carina II Dwarf Galaxy G 07 36 25.6 -57 59 57           ~ 86 0
27 NAME Car III Dwarf Galaxy G 07 38 31.2 -57 53 59           ~ 81 0
28 NAME UMa II Galaxy G 08 51 30.0 +63 07 48     13.3     ~ 410 0
29 NAME Antlia II Dwarf Galaxy G 09 35 32.8 -36 46 02           ~ 109 0
30 NAME Segue 1 G 10 07 03.2 +16 04 25     15.3     ~ 517 1
31 Z 64-73 G 10 08 28.12 +12 18 23.4   11.3 10.0     ~ 1284 1
32 NAME Sextans dSph LSB 10 13 02.9 -01 36 53   12 10.4     ~ 921 0
33 NAME UMa I Galaxy G 10 34 52.80 +51 55 12.0     14.4     ~ 355 1
34 NAME Willman 1 G 10 49 21.0 +51 03 00     15.2     ~ 345 0
35 NAME Leo Minor I Dwarf Galaxy G 10 57 03 +28 52.5     17.16     ~ 6 0
36 Z 126-111 G 11 13 28.13 +22 09 10.1   12.9 12.0     ~ 899 0
37 NAME Leo V LSB 11 31 09.60 +02 13 12.0     16.0     ~ 234 0
38 NAME Leo IV LSB 11 32 57.0 -00 32 00     15.1     ~ 419 1
39 NAME UMa III Cl* 11 38 49.8 +31 04 42           ~ 22 0
40 NAME Crater II Dwarf Galaxy G 11 49 14 -18 24.8           ~ 176 0
41 NAME Vir I Dwarf Galaxy LSB 12 00 09.6 -00 40 48           ~ 40 0
42 NAME Hydra II G 12 21 42.1 -31 59 07           ~ 118 0
43 NAME Coma Dwarf Galaxy G 12 26 59.0 +23 54 15     14.1     ~ 482 1
44 NAME Centaurus I G 12 38 20 -40 54.1     14.78     ~ 29 0
45 NAME CVn II dSph G 12 57 09.6 +34 19 12     16.1     ~ 287 2
46 NAME CVn I dSph G 13 28 03.5 +33 33 21     13.1     ~ 352 1
47 NAME Bootes III G 13 57 07.4 +26 46 30     12.6     ~ 115 1
48 NAME Bootes II G 13 58 00.0 +12 51 00     15.4     ~ 269 0
49 NAME Bootes Dwarf Spheroidal Galaxy G 14 00 00.0 +14 30 00     12.8     ~ 491 0
50 NAME Bootes V Dwarf Galaxy G 14 15 38 +32 54.8     16.84     ~ 10 0
51 Z 318-18 G 15 09 08.0 +67 13 21   13.60 10.6     ~ 1459 0
52 NAME Bootes IV LSB 15 34 45 +43 43.6           ~ 24 0
53 NAME Draco II Gl? 15 52 47.6 +64 33 55           ~ 138 0
54 NAME Hercules Dwarf Galaxy G 16 31 02.0 +12 47 30     14.0     ~ 379 1
55 Z 300-12 G 17 20 14.335 +57 55 16.39   12.40 10.6     ~ 1428 1
56 NAME Sagittarius II Gl? 19 52 40.5 -22 04 05           ~ 97 0
57 NAME Ind II G 20 38.9 -46 10           ~ 31 0
58 NAME Indus I Cl* 21 08 49.970 -51 09 48.60           ~ 68 0
59 NAME Pegasus IV G 21 54 09 +26 37.2           ~ 15 0
60 NAME Gru II G 22 04.1 -46 26           ~ 110 0
61 NAME Pegasus III LSB 22 24 22.6 +05 25 12           ~ 69 0
62 NAME Aquarius 2 G 22 33 55.5 -09 19 39           ~ 66 0
63 NAME Tuc II G 22 51 55.1 -58 34 08           ~ 192 0
64 NAME Grus I G 22 56 42.4 -50 09 48           ~ 126 0
65 NAME Pisces II G 22 58 31.0 +05 57 09     16.3     ~ 283 0
66 NAME Tuc V G 23 37.4 -63 16           ~ 84 0
67 NAME Phe II G 23 39 59.4 -54 24 22           ~ 107 0
68 NAME Tuc III G 23 56.6 -59 36           ~ 229 0

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