distances to galaxies - inaf-oac · 2011. 6. 17. · extragalactic stellar astronomy . the...
TRANSCRIPT
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
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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 !!!!
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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.
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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
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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
Spectral window 4497-4607Å
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
Spectral window 4438-4497Å
Nap
les 2
011
χi
spectral window 4438-4497Å
Nap
les 2
011
Χi
all windows
[Z] = -0.4±0.1
Nap
les 2
011
Spectral window 4117-4195Å
A3 IaTeff = 8500Klog g = 1.65
Nap
les 2
011
χi
spectral window 4117-4195Å
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
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
Vivian U, Urbaneja, Kudritzki, Jacobs, Bresolin, 2009, ApJ
740, 1120
Nap
les 2
011
B&A supergiants
in M33 -
reddening
Adopted byHST Key ProjectFreedman et al.2001
Vivian U, Urbaneja, Kudritzki, Jacobs, Bresolin, 2009, ApJ
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
Vivian U, Urbaneja, Kudritzki, Jacobs, Bresolin, 2009, ApJ
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
Adopted byHST Key ProjectFreedman et al.1994
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
Kudritzki, Gazak, Urbaneja
et al.
IoA
2011
Kudritzki, Gazak, Urbaneja
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