disk galaxies Joe Joel C. . Roed oedig iger (Queens) Stphane - - PowerPoint PPT Presentation

Stellar migrations and more in cluster disk galaxies

Joe Joel C. . Roed

• edig

iger (Queen’s) Stéphane Courteau (Queen’s) Patricia Sánchez-Blázquez (UNAM) Michael McDonald (MIT)

arXiv:1201.6361 Roediger et al. 2012, ApJ (in print)

Disk galaxies come in many Types (I)

Typ ype

I

Sur Surface brig brightn tness pro profil ile Exponential (> 5 Rd) Fra Fractio ion of

• f fi

fiel eld disk popu population

• n

(Gu (Guti tierr rrez et et al

• al. 20

2011)

20% For Formati tion sc scen enario Inside-out

Type I’s should have nega egati tive stellar age and metallicity gradients

(Ferguson & Clarke 2001; Mollá & Diaz 2005; Naab & Ostriker 2006)

Bland-Hawthorn et al. (2005); Vlajić et al. (2009)

See also NGC 7793 (Vlajić et al. 2011)

NGC 300 00

Disk galaxies come in many Types (II)

Typ ype

II

Sur Surface brig brightn tness pro profil ile Down-bending double exponential Fr Fractio ion of

• f fi

fiel eld disk popu population

• n

(Gu (Guti tierr rrez et et al

• al. 20

2011)

50% For Formati tion sc scen enario Inside-out + stellar migrations

Erwin et al. (2008) Roškar et al. (2008)

Stellar ages should in incr crease beyond break in Type II’s

(Roškar et al. 2008; Sánchez-Blázquez et al. 2009; Martínez-Serrano et al. 2009)

Fie ield ld Type II’s exhibit upturns in their age gradients

(de Jong et al. 2007; Barker et al. 2011; Yoachim et al. 2012; Radburn-Smith et al. 2012)

Disk galaxies come in many Types (III)

Typ ype

III

Sur Surface brig brightn tness pro profil ile Up-bending double exponential Fra Fractio ion of

• f fi

fiel eld disk popu population

• n

(Gu (Guti tierr rrez et et al

• al. 20

2011)

30% For Formati tion sc scen enario Minor merger(s)

Younger et al. (2007)

Type III’s might also harbour uptu turn rns in their age gradients Outer disk built up from in inner er disk isk star stars, akin to stellar migrations (Younger et al. 2007)

What about cluster disks?

McD cDonald ld et et al.

• al. (2011

2011) – g, r, i, z & H surface photometry for 286 Virgo galaxies

Morp rphol

• logy

N B/ B/Ti Lum Lumin inosity (M (Mi) Su Surfa rface br brigh ightn tnes ess (μe,i

e,i)

Size Size (re,i

e,i)

Sa-Sm 44 0 – 0.24

• 17.4 – -21.0 mag

21.3 – 23.3 mag arcsec-2 1.9 – 5.5 kpc

Roe Roedig iger et et al.

• al. (2011

2011a,b ,b) ) – colour/stellar population analysis of McDonald et al. data

a analysis of deeper imaging (< 28 mag arcsec-2) may alter these numbers b values from Gutierrez et al. (2011)

Outer disk structure depends on enrivonment

Environment Morp rphologies Typ ype co composition

I II III

Virgoa

Sa – Im

0.32 0.36 0.32 Fieldb

S0 – Sm

0.20 0.50 0.30

Age upturns are found in all disk Types ...

I II III

Bootstrap linear fits to inner and

• uter gradients
• f upturning age

profiles Lar Large e ra rang nge e in in up uptu turn stren strength th!

... and those upturns correlate with the breaks in Virgo Type II’s ...

(as predicted by simulations; Roškar et al. 2008, Sánchez-Blázquez et al. 2009; Martínez-Serrano et al. 2009)

Vir irgo Theory

Upturns also

• ffset from

breaks in field field Type ype IIs

(Yoachim et al. 2012)

Ty Type Po Positi tive Fla Flat Nega Negati tive Up Uptu turn

I

7 8 2 3

II

8 3 3 8

III

7 5 2 6

... but upturns are not that common overall

Models Virgo go Ty Type Po Positi tive Fla lat Ne Nega gati tive Up Uptu turn

I



II



III



I II III

Why do cluster and field disks differ?

Flat and positive age gradients are found most often near ear clu clust ster co core re Age gradients within Virgo disks do do not t co corre rrela late with their structure

Upturn

Summary

1. 1. Typ ype II dis disks s are are rarer rarer in in clu cluste ters s than than in in the the field field

• outer structure of disks sensitive

to repeated tidal forcing

2. 2. Age ge uptu pturn ph phen enomenon fou found am amongst t al all l dis disk k Type ypes s in in Vir Virgo go

• stellar migrations a generic

aspect of disk galaxy evolution?

3. 3. Flat lat an and d po positi sitive ag age e grad gradients s do dominate te am amongs gst t Virg Virgo dis disks ks

• tides and ram pressure stripping

mix and quench outer disks

For observ servers: Analyse deeper imaging (< 28 r-mag arcsec-2) for cluster disks to produce unmatched description of outer disk structure in dense environments (e.g., NGVS).

Future work

For theo theorists ts: Produce high-res hydrodynamic simulations of cluster galaxies, including ram pressure stripping and harassment.

See Roediger et al. (2012), arXiv:1201.6361