The GALEX Ultraviolet Virgo Cluster Survey (GUViCS): A Unified Picture of Galaxy EvoluCon

Transcription

1 The GALEX Ultraviolet Virgo Cluster Survey (GUViCS): A Unified Picture of Galaxy EvoluCon A. Boselli, E. Voyer, S. Boissier, O. Cuccia5, G. Consolandi, L. Cortese, G. Gavazzi, S. Heinis, Y. Roehlly, E. Toloba

2 The GALEX Ultraviolet Virgo Cluster Survey (GUViCS) Mapping ~ 300 sq.deg. of the Virgo cluster with GALEX All Imaging Survey (~200 sec) ~ 94% complete Medium Imaging Survcey (~ 1500 sec) ~ 65% complete (NUV band) ~ 1,200,000 detec5ons in the NUV (Voyer et al. 2014, submized to A&A)

3 The Sample All galaxies detected in the NUV band (2316 A) with: 12<RA<13h; 0<dec<20deg NUV(AB) < 22 mag vel<3500 km/s 854 galaxies

4 The Data FUV (1539 A) GALEX (62%) SDSS photometry (ugriz) (100%) & spectroscopy (nuclear Hα emission and Hδ absorp5on lines; 68%) WISE 22 μm (75%) Herschel 250 μm (64%) HI 21cm (ALFALFA + GOLDMine) (85%) Kinema5cs (ATLAS- 3D + de of Toloba et al.) (13%) 854 galaxies

5 GALEX AIS GALEX MIS X- rays VCC NGVS HeViCS

6 Galaxies in the velocity space

7 Galaxy density Voronoi tassella5on method to iden5fy the cluster substructures and calculate galaxy density Δρ = ρ/ρfield - 1

8 Colour- stellar mass relacon NUV- i vs Mstar rela5on to iden5fy galaxies in the red sequence, green valley and blue cloud NUV and i data corrected for dust azenua5on using WISE 22 μm data Filled dots: HI- def<0.4

9 Morphology (colour) segregacon

10 Massive galaxies Filled dots: slow rotators (major merging) Crosses: fast rotators

11 Massive galaxies Filled dots: slow rotators (major merging) Crosses: fast rotators

12 Massive galaxies Filled dots: slow rotators (major merging) mainly located within the caus5c and virial radius è cluster members since early epochs Crosses: fast rotators also outside the caus5c and the virial radius è more recently accreted

13 The role of environment on galaxy evolucon Filled dots: HI- def<0.4

14 The role of environment on galaxy evolucon Comparison with models (Boselli et al 2006; 2008) Starva5on Ram pressure stripping - Low efficiency - High efficiency (NGC 4569)

15 The role of environment on galaxy evolucon UV upturn: very old stellar popula5ons è old merging event? Starva5on Ram pressure stripping - Low efficiency - High efficiency (NGC 4569)

16 Dwarf galaxies Mstar < Mo

17 Dwarf galaxies The colour segrega5on effect is much stronger in dwarfs than in massive galaxies

18 Dwarf galaxies: ISM Filled dots: dwarf galaxies (Mstar<109.5 Mo) detected by Herschel at 250 μm è dust rich systems (ISM not fully removed)

19 Dwarf galaxies: nuclear SFR Filled dots: dwarf galaxies (Mstar<109.5 Mo) with HαEW> 3 A è nuclear star forma5on from residual gas kept in the core of the galaxy

20 A unified picture of galaxy evolucon: Massive early- type galaxies Massive ellip5cal galaxies are too massive to be formed by a simple quenching of the SFA of spirals They are all slow rotators They are all the most massive galaxies of each cluster substructure generally associated with the diffuse X- ray emission of the IGM In cluster A they are virialised within the poten5al well of the cluster They are characterised by a very old stellar popula5on (UV upturn) ê Formed by major merging events within the different subgroups at early epochs (pre- processing)

21 A unified picture of galaxy evolucon: Dwarf early- type galaxies Star forming dwarfs are totally lacking within cluster A They can be easily stripped of their gas in a ram pressure stripping event de are stripped of their ISM in cluster A The few slow rotators are located within the inner regions of cluster A associated with the and X- ray emission of the IGM. They are also virialised within the cluster Fast rotators are located mainly at the periphery of the cluster and are not virialised within the cluster ê The majority of de are formed aver a ram pressure stripping event; Those which entered the cluster at early epochs have been perturbed by gravitaconal interaccons (harassment)

22 The GALEX Ultraviolet Virgo Cluster Survey (GUViCS): A Unified Picture of Galaxy EvoluCon A. Boselli, E. Voyer, S. Boissier, O. Cuccia5, G. Consolandi, L. Cortese, G. Gavai, S. Heinis, Y. Roehlly, E. Toloba