Distances to galaxies - INAF-OAC · 2011. 6. 17. · Extragalactic stellar astronomy . The...

Distances to galaxies from

the brightest stars in the universe

Rolf Kudritzki

in collaboration with

Miguel UrbanejaFabio Bresolin

Vivian UZachGazak

requires independent accurate methods to

assess systematic effects

δH0 / H0 < 5%

Extragalactic stellar astronomy The perennial problem of extragalactic distances

patchy dust extinction

metallicity

dependenceof distance indicators

metal-poor

metal-rich

Nap

les 2

011

HII regions in M83HII regions in M83

4000Å 6000Å

Nap

les 2

011

Pagel, Edmunds, Blackwell et al. 1979

strong line method: R23 = f[N(O)/N(H)]

simple empirical calibration

but…

R23

depends on

Telectronnelectronnature of

ionizing stars

gas imhomog.

filling factors

depletion into

dust…..

Extragalactic stellar astronomy ΛCDM-universe

metallicity

of galaxies depends on their mass

metal-rich

metal-poor

metal-medium

WLM

NGC 300M81

Extragalactic stellar astronomy Tremonti

et al., 2004, ApJ

613, 898

50,000 starforming

galaxies with Sloan spectra

strong nebularemission lines:hydrogen,oxygen,nitrogen

Extragalactic stellar astronomy mass-metallicity

relationship

Rosetta stoneto understandgalaxy formationand chemical evolution!

However…It’s based on very simplified emission line analysis….

Tremonti

et al., 2004, ApJ

613, 898

Extragalactic stellar astronomy SDSS star forming galaxies

Kewley & Ellison 2008

mass –

metallicityrelationship

depends crucially on strong line method

calibration

supergiant stars will come to rescue !!!!

Nap

les 2

011

Extragalactic stellar astronomy the alternative –

quantitative spectroscopy of the brightest stars

©

Fabio Bresolin

IoA

2011 supergiants

–

objects in transition

B1–A4

Brightest normal stars

at visual light:

105..106

Lsun-7 ≥

MV

≥

-10 mag

tev

~ 103

yrsL, M ~ const.

ideal to determine

• chemical compos.• abundance grad.• SF history• extinction• extinction laws• distances

of galaxies

nearby supergiants

in Orion

1000 Lyrs

away

Rigel

IoA

2011 Flux weighted Gravity –

Luminosity Relationship (FGLR)

Kudritzki, Bresolin, Przybilla, ApJ

Letters, 582, L83 (2003)

M ~ g×R2

~ L×(g/T4) = const.

const.

with L ~ Mx

~ Lx(g/T4)x, x ~ 3

L1-x

~ (g/T4)x

or with Mbol

~ -2.5log L

Mbol

= a log(g/T4) + b FGLR

a =2.5 x/(1-x) ~ 3.75

B1-A4

L,M ~ const.

Nap

les 2

011

Example: LMC FGLR using Magellan/Mage

Urbaneja, Kudritzki, Pietrzynski, Gieren

et al., 2011

Nap

les 2

011

LMC BSG RV

and E(B-V)

∆RV

= 1.0

∆AV

= 0.12 mag

Urbaneja, Kudritzki, Pietrzynski, Gieren

et al., 2011

IoA

2011 Spectroscopic studies

beyond the Local Group

• selection of targets from wide field CMDs

• HST ACS imaging

• multi-object spectroscopy∆λ

~ 4-5 A with FORS @ VLT

LRIS @ Keck

Teff

~ 4%, ∆

log g ~ 0.05, metallicity

~ 0.1 dex

• galaxies out to 10 Mpc

Nap

les 2

011 pilot study

NGC 300NGC 300 – Sculptor Group (2 Mpc)

117 cepheids

70 blue supergiant spectra

Kudritzki, Urbaneja, Bresolin

et al. 2008, ApJ

681, 269

IoA

2011

The power of modern spectroscopy

Galactic template

Galactic template

NGC 300 A2 supergiant

•

A grid of NLTE model calculations

•

Late-B (B6) to mid-A (A3/A5)•

Luminosity class: Ia

to Ib/II•

12 metallicities

Z/Z_sun•

2.0, 1.4, 1.0, 0.7, 0.5, 0.4, 0.3, 0.25, 0.2, 0.14, 0.1, 0.05

•

Chemical composition•

H,He,C,N,O,Mg,S,Ti,Fe•

Ne,Na,Al,Si,P,K,Ca,Sc,V,Cr,

Mn,Co,Ni,Cr,Zn,Sr,Y,Zr,Ba

•

~ 6000 models in total

14,000 10,000Teff

[K]

log g

2.5

2

.0

1

.5

1.0

Nap

les 2

011

Balmer

jump fitting: Teff

Teff

= 9500K

bf-absorptionby hydrogenfrom 2nd

level

Nap

les 2

011

Teff

= 9250K

Balmer

jump fitting: Teff

Nap

les 2

011

Teff

= 9750K

Balmer

jump fitting: Teff

Nap

les 2

011

Teff

= 9500K

Balmer

jump fitting: Teff

Nap

les 2

011

Balmer

series fitting: log g = 1.55±0.1

H6

At fixed Teff

∆

log g = ±

0.05

Nap

les 2

011

Balmer

series fitting: log g = 1.55±0.1

H8

At fixed Teff

∆

log g = ±

0.05

Nap

les 2

011

A2 IaTeff

= 9500 Klog g = 1.45

HST/ACS + ground

Kudritzki, Urbaneja

& Bresolin

et al. 2008

SED fit E(B-V), RVAVextinction law

NGC 300A supergiant

Nap

les 2

011

E(B-V) distribution in NGC 300

Adopted byHST Key ProjectFreedman et al.2001

Distance 15%too large

Nap

les 2

011

NGC 300 (log g, log Teff

) -

diagram

40 25 15 Msun

B supergiants(Urbanejaet al., 2005) A supergiants

(Kudritzki et al., 2008)

Nap

les 2

011 Kudritzki, Urbaneja, Bresolin

et al, 2008, ApJ

681, 269

regression

Nap

les 2

011

Mbol

= 3.41{ log(g/T4eff,4

) -1.5} –

8.02 = 0.32 mag

Kudritzki, Urbaneja, Bresolin

et al., 2008, ApJ

681, 269

Study of metallicities

Nap

les 2

011

Metallicity: spectral window

Nap

les 2

011

[Z] = -1.3 …

+0.3

Nap

les 2

011

Spectral window 4497-4607Å

Nap

les 2

011


χ2i =SN

2 1npix

npixj=1 (Oj − Cj)2

Nap

les 2

011

χi

spectral window 4497-4607Å

Nap

les 2

011

another spectral window

Nap

les 2

011


Nap

les 2

011

χi


Nap

les 2

011

Χi

all windows

[Z] = -0.4±0.1

Nap

les 2

011


A3 IaTeff = 8500Klog g = 1.65

Nap

les 2

011

χi


Nap

les 2

011

Χi

all windows

[Z] = -0.5±0.15

Nap

les 2

011

Stellar metallicity

gradient in NGC300

■

B0 –

B3 supergiants●

B8 –

A4 supergiants---

log{Z/Z_sun} = -0.03 –

0.45•ρ/ρ0

= -0.03 –

0.08•d/kpc

Kudritzki, Urbaneja, Bresolin, Przybilla, Gieren, Pietrzynski, 2008, ApJ

681, 269angular galactocentric

distanceρ0

= 9.75 arcmin

≈

5.7kpc

“Extragalactic Pizza” IfA March 1st 2005 53 - 40

Extragalactic Stellar Spectroscopy

Stellar vs. HII Stellar vs. HII metallicitymetallicity

gradient gradient

----

Zaritsky

et al. (1994) ----

Dopita

&Evans (1986) ----

Kobolnicky

et al. (1999) ----

Denicolo

et al. (2002)

Almost identical with stellar regression!!!!

----

Pilyugin

(2001) ----

Pettini

& Pagel

(2004) Who is right???

Kudritzki

et al., 2008, ApJ

681, 265

auroral

line

nebular lines

The solution? Auroral

lines!!

28 auroral line detections(previously: 2)

VLT/FORS2NGC 300

Bresolin, Gieren, Kudritzki, Pietrzynsky, Urbaneja & Carraro 2009, ApJ, 700,

309

Nap

les 2

011

Bresolin,Gieren, Kudritzki

et al. 2009

Excellent agreement between auroral

lines and supergiants

!!

◦ ●

HII-

auroral□

* supergiants

HII-auroral

lines regression

supergiants

regression

this work

McGaugh91Tremonti

et al.2004

Kewley/Dopita2002

Pettini/Pagel2004

Auroral

lines vs. strong lines calibrations –

a horror story !!

Bresolin,Gieren, Kudritzki

et al. 2009

NGC 300

0.6 dex

Bresolin, Gieren, Kudritzki, Pietrzynsky, Urbaneja & Carraro

2009, ApJ, 700, 309

WLMWLMfaintest dwarf irregular in LGfew HII regions: [O] = -0.8

IoA

2011

A-supergiant: [Fe] = -1.00Urbaneja, Kudritzki, Bresolin

et al. 2008, ApJ, 684, 118

average of 6

A-supergiants: [Fe] = -0.87±0.07

IoA

2011 FGLR in WLM

FGLR distance d= 0.99 ±0.05

Mpc

Urbaneja, Kudritzki, Bresolin

et al.2008

ApJ, 684, 118

agrees with Cepheids, TRGB Pietrzynski

et al., 2008,

Rizzi

et al., 2007

IoA

2011An FGLR distance to M33

from A & B supergiants

Vivian U, Miguel Urbaneja, Rolf Kudritzki et al., 2009, ApJ

740, 1120

Published distances to M33method m-M (mag) authors

Cepheids 24.52 ± 0.14 Lee et al., 2002

24.62 ± 0.15 Freedman et al., 200125.53 ± 0.11 Scowcroft et al., 2009

TRGB 24.81 ± 0.15 Kim et al., 200224.69 ± 0.15 Tiede

et al., 2004

24.50 ± 0.15 McConnachie

et al., 2004 24.64 ± 0.15 Gallet

et al., 2004

HB 24.84 ± 0.16 Sarajedini

et al., 2000PNLF 24.86 ± 0.11 Ciardullo

et al., 2004

RR Lyrae 24.67 ± 0.16 Sarajedini

et al., 2000

LPVs

24.85 ± 0.13 Pierce et al., 2000H2

O masers 24.31 ± 0.45 Brunthaler

et al., 2005Binary 24.92 ± 0.12

Bonanos, Stanek, Kudritzki

et al., 2006

IoA

2011 A supergiants

in M33

Vivian U, Urbaneja, Kudritzki, Jacobs, Bresolin, 2009, ApJ

740, 1120

IoA

2011

B&A supergiants

in M33


740, 1120

Nap

les 2

011

B&A supergiants

in M33 -

reddening



740, 1120

Nap

les 2

011 B&A supergiants

in M33 –

FGLR

Vivian U, Urbaneja, Kudritzki et al. 2009

m-M = 24.93±0.11 mag

Nap

les 2

011

B&A supergiants

in M33

▪

B supergiants• A


740, 1120

shallow slope 0.07 dex/kpc

Nap

les 2

011 Cepheids

in M33

Scowcroft et al, 2009, MNRAS 396, 1287

Magrini

et al., 2007 metallicity

gradient

U, Urbaneja, Kudritzki

et al. 2009

Bresolin

2011

IoA

2011

M81 Keck LRIS

IoA

2011 M81 extinction


Distance too large

IoA

2011

the extinction problem

for ∆E(B-V) = 0.2

@ H-band ∆Aλ

= 0.12 mag∆d/d

= 5.5%

B

V

R

JH

K

IoA

2011

M81 FGLR

●

M81●

other galaxies

m-M = 27.62 ±

0.09 mag

Kudritzki, Gazak, Urbaneja

et al.

IoA

2011


et al.

IoA

2011


et al.

very shallow gradient: 0.02 dex/kpc

super solar [Z]

IoA

2011

NGC2403 3.5 MpcKeck LRISData taken January 2011

IoA

2011

NGC 4258 7 Mpc

“Maser Galaxy”

Keck LRIS March 26 –

28, 2011

IoA

2011

Bresolin, 2011auroral

lines

Zaritsky

et al., 1994strong lines

Metallicity

of NGC 4258

McGaugh, 1991strong lines

IoA

2011Cepheids

in NGC 4258

HII regions

Macri

et al. 2006, Riess

et al., 2009

using Zaritsky

et al., 1994

Bresolin

2011

IoA

2011 Blue supergiants

in NGC 4258

Keck LRIS March 26 –

28, 2011

Nap

les 2

011 NGC 4258, Mask 1, Slit 5

Teff

= 8300K, log g = 0.75[Z] = -0.2

Thirty Meter Telescope (TMT)

TMT on Mauna Kea

Nap

les 2

011

WFOS quantitative spectroscopy possible down to mV

~ 24.5 mag

with objects MV

≤

- 8 mag

m –

M ~ 32.5 mag

~ 30 Mpc

possible

chemical evolution studiesSFISM, extinction, extinction lawsdistances

10 objects per galaxy

Δ(m-M) ~ 0.1 mag

Conclusions and TMT/ELT perspectives

Nap

les 2

011

Gaia first accurate distances of MW BSGsMW BSG too far for Hipparcos

accurate calibration of FGLRso far: average of 8 galaxies

LMC calibration under way

Conclusions and Gaia perspectives

Distances to galaxies - INAF-OAC · 2011. 6. 17. · Extragalactic stellar astronomy . The...

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