Star Formation in the Local and Nearby Universe

Karina Caputi

Star Formation in Galaxies through Cosmic Times NOVA PhD Fall School 1-5 October 2012 The Evolution of the Star Formation Rate Density

Hopkins & Beacom (2006) The Local Group

stellar populations can still be individually resolved

M33

Credit: http://www.astro.ljmu.ac.uk

See e.g. Tolstoy et al. (2009) for a review The Milky Way

inside view makes its study a bit peculiar

Advantage: stellar populations can be individually resolved Disadvantage: full view requires model reconstruction

To estimate SFR in the Milky Way:

•Count HII regions •Count Young Stellar Objects (YSOs)

Credit: Churchwell et al. (2009) The integrated view

the ability of resolving stellar populations is quickly lost

but galaxies close enough for the study of detailed morphology and property gradients

NGC 5866 - HST NGC 1300 - HST M 51 (Whirlpool) - HST The Hubble Sequence

Credit: http://www.astro.ljmu.ac.uk/courses/phys134/cosmo.html The galaxy colour bimodality

Faber et al. (2007)

Baldry et al. (2004)

Observed: galaxy downsizing Detection of new star formation: UV diagnostics

Credit: NASA/JPL-Caltech Main past and present UV telescopes

Hubble Space Telescope (HST) -- 1990+ International Ultraviolet Explorer (IUE) -- 1978+

GALEX 2003+ UV spectra of local star-forming galaxies

P Cygni profile

Leitherer et al. (2010) Stellar winds - PCygni line profiles

present in star-forming galaxies at low and high z

Credit: P. Kudritzki Detection of new star formation: Balmer lines

Kniazev et al. (2000) Kennicutt (1992) Emission line maps with integral field spectroscopy

Alonso-Herrero et al. (2009) Seyfert Galaxies

Credit: Ho et al. (1993); A.Filipenko The BPT diagram

Baldwin, Phillips & Terlevich (1981)

Kewley et al . (2001)

Kauffmann et al. (2004) The mass-metallicity relation

9.4

9.2

9.0

8.8

12 + log(O/H) 8.6 2500 = 0.10 2000

8.4 1500

1000

8.2 Number of Galaxies 500 0 1.0 0.5 0.0 0.5 1.0 12 + log(O/H) Residuals 8.0 8 9 10 11 log(M ) *

Tremonti et al. (2004) Optical Observations

can perfectly be done from the ground 2-4m-class telescopes enough to survey local Universe and brightest high-z sources

SDSS 2.5m-diameter Telescope Revealing dust-obscured star formation

dust absorbs the UV photons of young stars, and then re-emits at infrared (IR) wavelengths

3 <λemit. < 1000 µm The dust effect on the UV/optical SED

dust attenuation affects more shorter wavelengths

0.4A f (λ)=f (λ) 10− λ obs. intr. × Local IR galaxies

the vast majority are ‘IR normal galaxies’ that form < 10 Msun / yr

Andromeda

Credit: ESA / Herschel SPIRE / HELGA; R. Gendler LIRGs and ULIRGs

rare in the local Universe

SFR > 20 Msun / yr and/or AGN

mostly the product of major mergers, but local large spirals can also be LIRGs

M82

Credit: HST / Spitzer Dust production

most of the dust we see in galaxies Supernovae can also be is produced in the envelopes of efficient dust factories AGB stars e.g. Renzini et al. (1985) e.g. Dwek (1998)

Credit: J. Hron SN in the Small Magellanic Cloud The mid-IR spectra of local starbursts

Spitzer IRS

[Ar II] [Ar III] [S IV] [Ne II] [Ne III] [S III] [O IV] [S III] [Si II]

H2 S(6)H2 S(5) H2 S(3) H2 S(2) H2 S(1) H2 S(0) PAHs 10.0

m Silicates Silicates µ

1.0

NGC 7252 NGC 1365 NGC 3310 NGC 7714 Mkn 52 NGC 1222 Flux density [Jy] normalized to 15 0.1 NGC 520 NGC 3628 NGC 4945

510 20 30 Rest frame wavelength [µm]

Brandl et al. (2006) The mid-IR spectra of local ULIRGs

H2 4 [NeII] PAH

3 H2

C H 2 2 2 H 2 Mrk 231 1

2.5 [NeII] H 2.0 PAH [NeIII] 2 [SIII] 1.5 PAH H2 1.0

0.5 HCN C2H2 Arp 220 0.0

[NeIII] H [NeV] 2 [NeII] 1.5 PAH

1.0 [SIV] H 2 05189-25 0.5 Spitzer IRS [NeII] [SIII] flux density (Jy) [NeIII] PAH H [NeV] 2 1.0 PAH H2

H2 [SIV] 0.5 Mrk 273 0.0 1.0 [NeII] [NeIII] H2 0.8

0.6 HCN 0.4 C2H2 0.2 08572+39 0.0 10 12 14 16 18 rest wavelength (microns) Armus et al. (2007) Polycyclic Aromatic Hydrocarbons (PAHs)

Credit: Spitzer Legacy

tracers of star forming regions at low and high z

‘left-overs’ of dust production process

Peeters et al. (2002); Smith et al. (2007); Tielens (2008) See: Puget & Léger (1989) Tielens (2008), ARA&A A galaxy Spectral Energy Distribution (SED)

Dust emission Stellar emission

1e+37

PAHs Luminosity (W) young stars old stars dust-obscured star formation stellar mass star formation & black-hole activity

1e+36

0.1 1 10 100 -6 Emitted wavelength (µm = 10 m)

dust grains of different sizes dominate different parts of the thermal dust emission The far-IR spectra of local starbursts

Mrk 231 - Herschel SPIRE

van der Werf et al. (2010) Molecular transitions

Dipole Moment:

eωr2 µ = e L 2c 2 L = mωre = j(j +1)¯h Image credit: R. Russell ! ¯hj ν = 2 ,j=1, 2,... 2πmre

Molecular hydrogen (H2) has no permanent dipole moment, so weak emission lines

use CO as a tracer Main past and present IR telescopes

IRAS - 1983 Spitzer Space Telescope -- 2003+

Herschel Space Observatory -- 2009+

ISO - 1995/1997 WISE -- 2009/2010 Star formation tracers: radio emission

Radio emission in star-forming galaxies is due to the synchrotron emission of accelerated particles produced in supernovae

M82 - eMerlin/VLA radio (5 GHz) map

Credit: http://www.jodrellbank.manchester.ac.uk/news/2004/connected/ The infrared-radio correlation

first studied by van der Kruit (1971, 1973)

Condon et al. (1982) Atomic gas in local galaxies: HI surveys

emission produced by the H atom spin flip (hyperfine line at 21 cm)

Westerbork Radio Telescope

M83 Credit: B. Koribalski ATCA

See e.g. van der Hulst et al. (2001); Morganti et al. (2005); Oosterloo et al. (2010) The Tully-Fisher relation

correlation between the rotational velocity of a galaxy and its luminosity

(applies to spiral galaxies)

rotational velocity derived from HI line Doppler broadening

the physical parameter governing the correlation is the galaxy mass

Image credit: http://abyss.uoregon.edu/~js/ast123/lectures/lec13.htm The combined view of a local star-forming galaxy

Credit: S. Vogel