Is Abell 1213 an Assembling Cluster of

Galaxies?

Omar López-Cruz (omarlx@inaoep.mx) Christopher Añorve (Ph.D.student)Héctor Javier Ibarra-Medel(M.Sc.

student)Juan Pablo Torres-Papaqui

(Posdoc) Coordinación de Astrofísica

Instituto Nacional de Astrofísica, Optica y Electrónica (INAOE)

Santa María Tonatzintla, Puebla, México

Recontres de Moriond 2010, March, 2010

Clusters & the Web

Moderate Moderate clustercluster

Embedded in supercluster, of central cluster (cf. Virgo in Local SC)

Void regionVoid region

Massive Massive clusterclustercf. Perseus cluster

Cluster & Web

Moderate Moderate clustercluster

Embedded in supercluster, of central cluster (cf. Virgo in Local SC)

Void regionVoid region

Supercluster Ridge:Supercluster Ridge:a filament with several cluster a filament with several cluster peaks (cf. peaks (cf. Perseus supercluster)Perseus supercluster)

Massive Massive clusterclustercf. Perseus cluster

Clusters and The Cosmic Web

Courtesy of Platen (Ph.D. Thesis 2009, Groningen), Aragón-Calvo, & van de Weygaert.

tm given by solving the Friedmann equations for a closed model:

€

tm =π

2H i

Ωp t i( )

Ωp t i( ) −1[ ]3/2 =

3π

32Gρ p tm( )

⎡

⎣ ⎢

⎤

⎦ ⎥

1/2

Overdensity at the turn-around tm:

€

ρ tm( ) = 6πGtm2

( )−1

Extrapolating linear-theory (~ t2/3):

€

+ tm( ) =ρ p tm( )

ρ tm( )−1=

3π

4

⎛

⎝ ⎜

⎞

⎠ ⎟2

−1 ≈ 4.6

€

+ tm( ) = δ+ ti( )tm

ti

⎛

⎝ ⎜

⎞

⎠ ⎟

2 / 3

= δ+ ti( )3π

4

⎛

⎝ ⎜

⎞

⎠ ⎟2 / 3 Ω p ti( )

2 / 3

δi

=3

5

3π

4

⎛

⎝ ⎜

⎞

⎠ ⎟2 / 3

≈1.07

The Top Hat Model

Hierarchical Galaxy Formation

Merging of smaller fragments into larger structuresCan be highly dissipative, leading to:

Bursts of star formation Fuelling of AGN Formation of ellipticals and bulges

Early stages of a dissipative merger of gas-rich galaxies

Late stages

Barnes & Hernquist 1996

Gas rapidly sinks to the centre, where it can fuel starburst and/or an AGN

AGN in Clusters

Selection X-ray point sources, radio FRII, Optical. It has been argued that X-ray selection is better than optical selection (Martini and collaborators). There is a hint of evolution Radio-X-ray-Optical

The number of AGN in rich clusters about 1 source within 1 Mpc. (148 clusters at 0.1 z0.9, 230 sources, 1.5 sources per cluster, Gilmour, Best, & Almaini 2009).

The fraction of AGN in clusters evolves rapidly with redshift, faster than AGN in the field (e.g., Galametz et al. 2009). AGN Butcher-Oemler Effect!!!

At z~1 van Breukelen et al. (2009) have suggested that AGN are almost vanished in virialiazed clusters while the fraction is large in non-virialized clusters.

…But, at low-z5% of all galaxies at low-z are AGN, mostly

low luminosity AGN (Ho 2008) Some cD are radio-laud galaxies (Matthews

et al. 1964) (19% of all BCG; 93% have Lradio

≥ 1023 W/Hz; Croft et al. 2007). Clear excess of AGN in the center of X-ray selected clusters (Lin & Mohr 2007)

Starbursts and Irr are vanished in the central regions of clusters.

Colors of galaxies indicate passive evolution; hence there are very low chances of seeing major action et low-z.

Searching for activity in Clusters

Ibarra-Medel et al. are searching for H in clusters using SDSS spectra for 120 Abell clusters.

Christoper Añorve has developed TORTUGAS (Tortured by GALFIT (Peng et al. 2003) surface brightness modeling). Two components Sérsic bulge+ exponential bulge to 2300 galaxies in 11 clusters at 0.02 < z< 0.07).

J. P. Torres-Papaqui applies STARLIGHT (Cid Fernández et al. 2005, http://www.starlight.ufsc.br/) to SDSS spectra.

We Stumbled into A1213!! Abell is an ARC=1 (Bgc= 300, Yee & López-Cruz

1999), irregular cluster (BM III) at z = 0.047. Three dominant galaxies.

We found 226 galaxies with spectra in SDSS within a 2 Mpc radius, 85 galaxies turned out to be members (Yahil & Vidal 1977), 22 galaxies had prominent H in emission.

After analyzing membership. We found that A1213 a velocity dispersion = 532.49 km/s (c.f. ROSTAT), its virial mass is Mv = 1.9X1014

M (Rvir = 0.6 Mpc), and a mass-to-light ratio M/L=126.

We found 11 of galaxies with H in emission and one radio galaxy within 1 Mpc.

Abell 1213 in LOCOS

LOw-Redshift Cluster Optical Survey (LOCOS, López-Cruz et al. 2010). 43 T2KA + 10 MOSA with KPNO 0.9m, BRI

Barkhouse, Yee, & LC, 2009, dwarf/ Giant galaxy population.

Barkhouse et al. 2007, Luminosity Functions

López-Cruz et al. 2004, Color-Magnitude Relation

The Caustics for A1213

This kind of analysis was pioneered by Regös & Geller (1989)

STARLIGHT ON SDSS

AGN, Seyfert

Diagnostic Diagrams

Activity in cluster members:

11 AGN + 1 Radio Galaxy (not shown)

10 SF/AGN

19 SF

Kewley et al. 2006

A multiwavelength View of A1213

RED- XMM

GREEN- FIRST

BLUE- LOCOS

white circles: AGN

Yellow circles:LLAGN

Magenta squares: AGN/SF

Crosses: starforming galaxies

A1213 radio halo?

Giovannini et al. 2009

Lx= 1X1043 erg/s

this is ten times lower that average.

Close-Up

Signs of galaxy interactions are present, plumes, stretched” spiral (UGC 6292), other SS have been seen in the Arp catalog (e.g. Arp 31), UGC 6292 =76 Kpc. We suggest SSS0

SS Galaxies S0?

Arp 31 (Integral Sign, 3%) Dubinski for PAndAS

TORTUGAS AT WORK

An Alternative Plausible Origin for S0 galaxies

We have devised a new morphological approach using an ellipticity vs. B/T plane.

The distribution of the Sérsic Index for

Ellipticals

n = 2.5 1.2

On the Origin of S0 galaxies

From the analysis of 2300 galaxies in 11 low-z clusters (Añorve, 2010)

Mode of the total luminosity:E (R=-20.85 mag), S0 (R=-20.69 mag), S (R=-20.82 mag)S0 are less luminous that E and SMode of the bulge luminosity:E (R=-20.3mag), S0 (R=-20.01 mag), S (R=-19.21 mag)The bulges of S0 and E are brighter than those of SMode of the Sérsic index E (n=2.4), S0 (n=2.2), S (n=1.2) The S0 bulges depart from S seudobulges.

If S0 originated from S the disks as well as the bulges of the progenitor spirals have to be modified.

This is an alternative to simple ram pressure stripping scenario.

Cosmological Test?

Cluster population at any one cosmic epoch very sensitive to cosmology (structure growth dependence).

Borgani &

Guzzo

2001

Less Activity Virialization

Richstone, Loeb, & Turner (1992) proposed a test where the incidence of substructure was set by the mean density at recombination.

Caveat: substructure is hard to evaluate!!!We propose to measure the degree of activity

(AGN or starburst within R200 or virial radius) in a volume limited sample of richness 1 clusters using the method outlined in this talk and confronted with Borgani’s simulations.

Conclusions

Abell 1213 is a probable assembling cluster Large number of AGN (12) and Star Forming (19)

which is more common to high-z clusters (0.5<z<0.1).

Stretched Spirals could become S0 in clusters with low hot gas. This can be a viable mechanism to generate S0 in the field, as well. No Ram Pressure.

A1213 provides a detailed view of cluster assembling that can be used to compare with clusters at high-z

We propose that the degree of activity in a volume limited sample confronted with numerical simulations can be used as a cosmological test.

Clusters & the Web

Clusters at the intersections of filamentary features

Virgo consort.

Clusters & The Web

Clusters at the intersections of filamentary features

Virgo consort.

Perturbation treated as a separate FLRW universe

The Top-Hat Spherical Collapse

€

ρp tm( ) = ρ c t i( )Ωp t i( )Ωp t i( ) −1

Ωp t i( )

⎡

⎣ ⎢

⎤

⎦ ⎥

3

Density at the epoch of maximum expansion (tm):

In a similar way, at the collapse (tc=2tm):

Condition of virialization:

€

ρ+ t c( ) =t c

tm

⎛

⎝ ⎜

⎞

⎠ ⎟

2 / 3

ρ + tm( ) ≈1.69

KUKE −=+=

Linear-theory extrapolation:

m

2

m R

GM

5

3E −==U

vir

2

vir R

GM

5

3

2

1

2

UE −=−=

virm RR 2=

€

ρp(t c)

⟨ρ (t c)⟩=

t c

tm

⎛

⎝ ⎜

⎞

⎠ ⎟

2Rm

Rvir

⎛

⎝ ⎜

⎞

⎠ ⎟

3ρ p(tm )

⟨ρ(tm )⟩=18π 2 ≅178

Total energy at turn-around:

Total energy at virial equilibrium: