[Astronomy seminar] Astronomy Department Seminar - September 17th Nushkia Chamba

[Astronomy seminar announcements]

Reminder of Nushkia's seminar in ~35 min

On 13/09/2021 11:11, Chris Usher wrote:
>
> Hello
>
> On Friday the 17h we have the third astronomy seminar of the year with 
> our own Nushkia Chamba (Stockholm University) speaking via Zoom at 10:30.
>
> *Unveiling the outskirts of galaxies using deep imaging *
>
> The traditional measurement of the size of galaxies, the effective 
> radius, is a relic of the epoch when shallow imaging was unable to 
> capture the full extension of astronomical sources. However, current 
> deep imaging surveys have revolutionised our view of galaxies and the 
> characteristics of their faint outskirts, allowing us to regard 
> critically our own conventions. From this perspective, it is time to 
> move from a size definition based on the light concentration of 
> galaxies, the effective radius, to a definition that intuitively 
> captures the concept of the size of galaxies, such as its edge or 
> boundary. In this talk, a physically motivated definition for the size 
> of a galaxy based on the gas density threshold value for star 
> formation in galaxies is studied. Remarkably, the new size definition 
> not only captures what the human visual system identifies as the edge 
> of a galaxy, but also dramatically decreases the scatter in the 
> stellar mass–size relation by more than a factor of two. Compared to 
> other size measures, the new parameter is unique in that it also 
> unifies galaxies spanning five orders of magnitude in stellar mass on 
> a single mass–size relationship. To place this discovery in the 
> context of galaxy formation and evolution, its application is 
> discussed on the understanding of the origin of discs and the nature 
> of ultra-diffuse galaxies.
>
> We are trying something new this year with leaving the Zoom call open 
> after the formal hour of the seminar is up to allow the speaker, if 
> they wish, to chat informally with anyone who is interested.
>
> Thanks
>
> Chris and Tine
>
> Christopher Usher is inviting you to a scheduled Zoom meeting.
>
> Topic: Astronomy Department Seminar - Nushkia Chamba
> Time: Sep 17, 2021 10:30 AM Stockholm
>
> Join Zoom Meeting
> https://stockholmuniversity.zoom.us/j/68003268702?pwd=Q085dHZrT0Y0djZHelZNL3RVb2x0Zz09 
>
>
> Meeting ID: 680 0326 8702
> Passcode: eRmiTeXA
> One tap mobile
> 46844682488,,68003268702
>
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