<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<div style="font-family: Aptos, Aptos_MSFontService, -apple-system, Roboto, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(33, 33, 33);" dir="auto">
Reminder of this today at 1pm!</div>
<div style="font-family: Aptos, Aptos_MSFontService, -apple-system, Roboto, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(33, 33, 33);" dir="auto">
<br>
</div>
<div style="font-family: Aptos, Aptos_MSFontService, -apple-system, Roboto, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(33, 33, 33);" dir="auto">
Joe</div>
<div id="ms-outlook-mobile-body-separator-line" data-applydefaultfontstyles="true" dir="auto" style="font-family: Aptos, Aptos_MSFontService, -apple-system, Roboto, Arial, Helvetica, sans-serif; font-size: 12pt;">
<div style="font-family: Aptos, Aptos_MSFontService, -apple-system, Roboto, Arial, Helvetica, sans-serif; font-size: 12pt;">
<br>
</div>
</div>
<div id="ms-outlook-mobile-signature" dir="auto" style="font-family: Aptos, Aptos_MSFontService, -apple-system, Roboto, Arial, Helvetica, sans-serif; font-size: 12pt;">
<div style="font-family: Aptos, Aptos_MSFontService, -apple-system, Roboto, Arial, Helvetica, sans-serif; font-size: 12pt;">
<br>
</div>
</div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Joseph Butler <Joseph.Butler@nottingham.ac.uk><br>
<b>Sent:</b> Monday, January 12, 2026 1:04:17 PM<br>
<b>To:</b> astro@nottingham.ac.uk <astro@nottingham.ac.uk><br>
<b>Subject:</b> Lunch Talk - 15/01/26</font>
<div> </div>
</div>
<div style="line-break:after-white-space"><span style="font-size:14px">Hi all,</span>
<div><span style="font-size:14px"><span><br>
</span><span>This week’s lunch talk will be given by Hua Gao, and will take place on Thursday 15th January at 1pm in A113. Title and abstract below.</span></span>
<div><span style="font-size:14px"><span><br>
</span><span><b>Title:</b> <i>Euclid Q1: A dichotomy between the stellar haloes of late-type and early-type galaxies</i></span></span></div>
<div><span style="font-size:14px"><span><br>
<b>Abstract:</b> We study stellar haloes for a sample of ∼70k central galaxies with 9 ≤ log(M⋆/M⊙) < 12 and 0.2 ≤ z < 0.8 in the Euclid Quick Data Release 1 (Q1) fields. The Q1 images are post-processed with a pipeline that is optimized for preserving diffuse
low-surface-brightness emission. We split the central galaxies by stellar mass and redshift and stack the images in each bin for late-type (LTGs) and early-type galaxies (ETGs) separately. We </span><span>then measure the radial surface brightness profiles
and colour profiles of the stacked galaxies. We can measure the surface brightness profiles out to > 10Re at 3σ detection limits for massive centrals (log(M⋆/M⊙) > 10) at all redshifts. We find that ETGs have larger stellar halo fractions and redder stellar
haloes than LTGs at the same redshift and stellar mass. The stellar haloes are bluer than the main body of galaxies in both optical–NIR and NIR colours, except for the least massive galaxies. We suggest that galaxy assembly bias and galactic conformity drive
the systematic differences between the stellar halo fractions and their colours of LTGs and ETGs.</span><span><br>
</span><span><br>
</span></span></div>
<div><span style="font-size:14px">Thanks,</span>
<div dir="auto" style="color:rgb(0,0,0)"><span style="font-size:14px">Joe</span></div>
<div></div>
</div>
</div>
</div>
</body>
</html>