1<!DOCTYPE HTML> 2<!-- 3 Paradigm Shift by HTML5 UP 4 html5up.net | @ajlkn 5 Free for personal and commercial use under the CCA 3.0 license (html5up.net/license) 6--> 7<html lang="en-US"> 8 9<head> 10 <title>SAGA Survey III</title> 11 <meta charset="utf-8" /> 12 <meta name="viewport" content="width=device-width, initial-scale=1" /> 13 <link rel="preload" href="assets/css/main.css" as="style" /> 14 <link rel="preload" href="images/bg.jpg" as="image" /> 15 <link rel="preconnect" href="https://fonts.googleapis.com" /> 16 <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin /> 17 <link rel="preconnect" href="https://cdnjs.cloudflare.com" crossorigin /> 18 <meta name="description" 19 content="The SAGA Survey. III. A Census of 101 Satellite Systems around Milky Way-mass Galaxies" /> 20 <meta name="keywords" content="SAGA, SAGA Survey, astrophysics, cosmology, Milky Way, galaxy, satellite, e-poster" /> 21 <meta name="creator" content="Yao-Yuan Mao"> 22 <meta name="twitter:card" content="summary_large_image" /> 23 <meta name="twitter:creator" content="@yaoyuanmao" /> 24 <meta property="og:url" content="https://sagasurvey.org/paper3/" /> 25 <meta property="og:title" content="The SAGA Survey: Paper III" /> 26 <meta property="og:description" 27 content="The SAGA Survey. III. A Census of 101 Satellite Systems around Milky Way-mass Galaxies" /> 28 <meta property="og:image" content="https://sagasurvey.org/paper3/images/saga_og.jpg" /> 29 <meta property="og:image:url" content="https://sagasurvey.org/paper3/saga_og.jpg" /> 30 <meta property="og:image:secure_url" content="https://sagasurvey.org/paper3/saga_og.jpg" /> 31 <meta property="og:image:type" content="image/jpeg" /> 32 <meta property="og:image:alt" content="The SAGA Survey: Paper III Poster Front Page" /> 33 <meta property="og:type" content="website" /> 34 <link rel="stylesheet" href="assets/css/main.css" /> 35</head> 36 37<body class="is-preload"> 38 39 <!-- Wrapper --> 40 <div id="wrapper"> 41 42 <!-- Intro --> 43 <section class="intro" id="intro"> 44 <header> 45 <h1>The SAGA Survey III</h1> 46 <p>101 satellite systems around galactic analogs</p> 47 <p><a href="https://doi.org/10.3847/1538-4357/ad64c4">Full Paper III on arXiv</a></p> 48 <p><a href="https://yymao.github.io/">Yao-Yuan Mao</a> and the <a href="../team">SAGA Survey Team</a><br /> 49 DR3 Paper Posters: III - <a href="../paper4">IV</a> - <a href="../paper5">V</a> 50 51 </p> 52 <p><a href="../">← Back to Homepage</a></p> 53 <ul class="actions"> 54 <li><a href="#design" class="arrow scrolly"><span class="label">Start</span></a></li> 55 </ul> 56 </header> 57 <div class="content"> 58 <span class="image fill" data-position="center"><img src="images/bg.jpg" 59 alt="Images of SAGA satellites (as website background)" /></span> 60 </div> 61 62 </section> 63 64 <!-- Section --> 65 <section id="overview"> 66 <header> 67 <h2>Survey Overview</h2> 68 </header> 69 <div class="content"> 70 <p style="font-size: 90%; text-align: center; margin: 0 auto;"><i>Click on figures below to enlarge.</i></p> 71 72 <!-- Section --> 73 <section> 74 <header> 75 <strong>Searching for small galaxies around Milky Way-mass galaxies</strong> 76 <p>The SAGA Survey is a galaxy redshift survey that characterizes satellite systems around Milky Way-mass galaxies at 25 to 40 Mpc, filling in in the regime where we can survey hundreds of MW-mass satellite systems and still obtain a sizable satellite population per system.</p> 77 </header> 78 <div class="content"> 79 <div class="gallery"> 80 <a href="images/saga-p3-f01.png" class="landscape"><img src="images/saga-p3-f01.jpg" 81 alt="SAGA Survey in context, illustrated" /></a> 82 </div> 83 </div> 84 </section> 85 <section> 86 <header> 87 <strong>101 Milky Way-mass satellite systems</strong> 88 <p>We have surveyed 101 Milky Way-mass systems, obtaining spectra for hundreds of objects per square degree within 300 kpc (in projection) of each host galaxy, covering about 85 square degrees of sky. 89 We identify Milky Way-mass hosts using a combination of stellar mass, halo mass, and mild isolation criteria (that still allow Local Group like systems).</p> 90 </header> 91 <div class="content"> 92 <div class="gallery"> 93 <a href="images/saga-p3-f02.png" class="landscape"><img src="images/saga-p3-f02.jpg" 94 alt="SAGA Survey Footprint and Host Properties" /></a> 95 </div> 96 </div> 97 </section> 98 <section> 99 <header> 100 <strong>So many satellites!</strong> 101 <p>Among the 101 systems we have identified 378 satellites, the majority of which have their first redshift measurements by SAGA. This figure shows the satellite galaxy images grouped by satellite systems. Within each system the satellite images are sorted from bright to faint. The number of confirmed satellites per system ranges from 0 to 13. Four of the 101 systems have the same level of survey completeness but do not have any confirmed satellites. 102 </p> 103 </header> 104 <div class="content"> 105 <div class="gallery"> 106 <a href="images/saga-p3-f03.jpg" class="landscape"><img src="images/saga-p3-f03_th.jpg" 107 alt="Images of 378 SAGA satellites, grouped by system." /></a> 108 </div> 109 </div> 110 </section> 111 </div> 112 </section> 113 114 <!-- Section --> 115 <section id="science"> 116 <header> 117 <h2>Science Highlights</h2> 118 </header> 119 <div class="content"> 120 <p style="font-size: 90%; text-align: center; margin: 0 auto;"><i>Click on figures below to enlarge.</i></p> 121 122 <section> 123 <header> 124 <strong>Satellite stellar mass functions</strong> 125 <p>We can now construct the satellite stellar mass functions for 101 Milky Way analogs, providing a clear picture of the system-to-system scatter in the satellite populations. 126 In the mass range the SAGA Survey focuses on, the number of satellites our Milky Way has is average when compared to the SAGA systems. However, most SAGA systems that have a massive satellite (like the LMC) host more satellites than the Milky Way has! 127 </p> 128 </header> 129 <div class="content"> 130 <div class="gallery"> 131 <a href="images/saga-p3-f04.png" class="landscape"><img src="images/saga-p3-f04.jpg" 132 alt="Satellite stellar mass functions for 101 Milky Way analogs" /></a> 133 </div> 134 </div> 135 </section> 136 137 <section> 138 <header> 139 <strong>Who has more satellites?</strong> 140 <p>With 101 satellite systems, we can explore what host or system properties correlate most strongly with the satellite abundance. We found the mass of the most massive satellite has the strongest correlation (more to the right) with satellite abundance in the SAGA systems. This correlation is even stronger than the correlation between halo mass and satellite abundance (yes, it sounds surprising, but is actually expected from simulations!) 141 </p> 142 </header> 143 <div class="content"> 144 <div class="gallery"> 145 <a href="images/saga-p3-f05.png" class="landscape"><img src="images/saga-p3-f05.jpg" 146 alt="Correlation between satellite abundance and host or system properties." /></a> 147 </div> 148 </div> 149 </section> 150 151 <section> 152 <header> 153 <strong>Co-rotating satellite plane/pairs?</strong> 154 <p>Among SAGA satellite systems, we find no strong evidence for co-rotating planes of satellites (which, if they exist, should appear as an excess above the horizontal band in this figure). There is, however, a small excess of close satellite pairs (near the right). We also found the satellites in close pairs tend to have a small velocity difference. 155 </p> 156 </header> 157 <div class="content"> 158 <div class="gallery"> 159 <a href="images/saga-p3-f06.png" class="landscape"><img src="images/saga-p3-f06.jpg" 160 alt="Signal of co-rotating satellite planes, or the lack of" /></a> 161 </div> 162 </div> 163 </section> 164 165 <section> 166 <header> 167 <strong>How many satellites are quenched?</strong> 168 <p>The quenched fraction of SAGA satellites increases with decreasing stellar mass, as one would expect. The SAGA satellite quenched fraction is lower than that of the Local Group (except for at LMC-mass scale), but by only about 1Ï when considering the system-to-system scatter. In <a href="../paper4">Paper IV (Geha+ 2024)</a> we further explore the star-forming properties of SAGA satellites and correlations between quenched fraction and host galaxy properties.</p> 169 </header> 170 <div class="content"> 171 <div class="gallery"> 172 <a href="images/saga-p3-f07.png" class="landscape"><img src="images/saga-p3-f07.jpg" 173 alt="Quenched Fraction of SAGA satellites, compared with that of the Local Group satellites and of isolated field galaxies" /></a> 174 </div> 175 </div> 176 </section> 177 178 <section> 179 <header> 180 <strong>Comparing with ÎCDM predictions</strong> 181 <p>The satellite abundance observed in SAGA systems is consistent with theoretical predictions based on Lambda-Cold Dark Matter simulations augmented by a galaxy-halo connection model. The model used here, UM-SAGA, is an extension to UniverseMachine and attempts to capture environmental quenching with halo assembly histories. Read more about UM-SAGA and its predictions in <a href="../paper5">Paper V (Wang+ 2024)</a>. 182 </p> 183 </header> 184 <div class="content"> 185 <div class="gallery"> 186 <a href="images/saga-p3-f08.png" class="landscape"><img src="images/saga-p3-f08.jpg" 187 alt="Comparing SAGA satellite abundance with ÎCDM predictions" /></a> 188 </div> 189 </div> 190 </section> 191 </div> 192 </section> 193 194 <!-- Section --> 195 <section id="beyond"> 196 <header> 197 <h2>Beyond Satellites</h2> 198 </header> 199 <div class="content"> 200 <p style="font-size: 90%; text-align: center; margin: 0 auto;"><i>Click on figures below to enlarge.</i></p> 201 202 <section> 203 <header> 204 <strong>So many more galaxy redshifts!!</strong> 205 <p>In addition to all these cool things that we learn from the SAGA satellite systems, the SAGA Survey obtained about 46,000 redshifts for galaxies that are within the SAGA footprint but not associated with those satellite systems. These redshifts are for galaxies that are faint and low-redshift, and hence can enable a wide range of studies, such as <a href="https://ui.adsabs.harvard.edu/abs/2022ApJ...927..121W/abstract">J.F.Wu+ 2022</a>
205 which uses this sample to train machine learning methods to identify other low-redshift galaxies with photometric data only, and <a href="https://ui.adsabs.harvard.edu/abs/2024arXiv240116469K/abstract">Kado-Fong+ 2024</a> which uses the SAGA background sample to constrain the mass loading factor. 206 </p> 207 </header> 208 <div class="content"> 209 <div class="gallery"> 210 <a href="images/saga-p3-f09.png" class="landscape"><img src="images/saga-p3-f09.jpg" 211 alt="Redshift and stellar mass distribution of SAGA background galaxies" /></a> 212 </div> 213 </div> 214 </section> 215 </div> 216 </section> 217 218 <!-- Section --> 219 <section id="contact"> 220 <header> 221 <h2>Want to know more?</h2> 222 </header> 223 <div class="content"> 224 <p>See <a href="..">the SAGA Survey Website</a> for other SAGA papers and <a href="../data">data access</a>! 225 </div> 226 </section> 227 228 <!-- Copyright --> 229 <div class="copyright"> 230 © 2024 <a href="https://yymao.github.io/">Yao-Yuan Mao</a> & <a href="https://sagasurvey.org">SAGA Survey</a>. All rights reserved. Design: <a href="https://html5up.net">HTML5 UP</a>. 231 </div> 232 233 </div> 234 235 <!-- Scripts --> 236
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