exploring the local group massive star content with 2-4m telescopes at orm and caha s. simón-díaz...
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Exploring the Local Group massive star content with 2-4m telescopes at ORM and CAHA
S. Simón-Díaz (IAC)
on behalf of the
IAC (PI. A. Herrero)CAB/CSIC (PI. F. Najarro)
UA (PI. I. Negueruela)IAA/CSIC (J. Maíz Apellániz)
massive star groups
+ M. Garcia, A. Marco, J. Lorenzo, A. Sota ...
Science with the optical-infrared telescopes at CAHA and ORM in the coming decade Madrid, 2012 March 22nd
Exploring the Local Group massive star content
* For the infrared part see Ignacio Negueruela’s talk (just after me)
Milky Way
The GOSSS project
- spectral types- catalogue- atlas - binaries
The IACOB project
- vsini / macrot.- stellar/wind parameters- abundances- binaries- time-dependent phenomena
+ IACOB-sweG
+ Detailed studies of selected candidates
+ Detailed study of binaries
+ Detect and characterize OB associations
Things we are doing / plan to do using optical* telescopes at CAHA and ORM
* For the infrared part see Ignacio Negueruela’s talk (just after me)
- Detect luminous blue stars (B Sgs, O stars, LBV, WRs) - Characterize OB associations - Spectral types
- Stellar & wind parameters- Abundances in a evolutionary context- 1D/2D abundance distributions- Detailed studies of selected candidates
Local Group galaxies (other than the MW)
Things we are doing / plan to do using optical* telescopes at CAHA and ORM
M33
M31
Exploring the Local Group massive star content
R: > 15000 8000-10000 5000 2000-3000
Spectral types: More than enough ok ok ok
Stellar/wind param.: Perfect feasible feasible at limit
Abundances: Optimal good feasible at limit
vsini_min (km/s) < 20 30-40 60 100-150
Binary detection < 7 km/s ~10 km/s ~20 km/s ~40 km/s
Exploring the Local Group massive star content (optical spectroscopy)
What can we do depending of the characteristics of the spectra?
Resolving power
** Nebular (HII spectrum) contamination **
SNR/pixel: > 150 100-150 50-100 < 50
Spectral types: More than enough ok ok too bad
Stellar/wind param.: Perfect good at limit too bad
Abundances: Optimal good at limit too bad
vsini Optimal possible at limit too bad
What can we do depending of the characteristics of the spectra?
Signal-to-noise ratio
Exploring the Local Group massive star content (optical spectroscopy)
3700 – 7000 A : Optimal
4000 – 4700 A : Minimum requirement for spectral types
4000 – 5000 A + H : Minimum requirement for quantitative spectroscopy
(stellar & wind parameters + abundances)
SiIII 4552 & OIII 5591 : very important lines for vsini (B & O-type stars)
What can we do depending of the characteristics of the spectra?
Spectral range coverage
Exploring the Local Group massive star content (optical spectroscopy)
Exploring the Local Group massive star content
Milky Way
Science with the optical telescopes at CAHA & ORM
The GOSSS project (PI. Maiz Apellaniz)
The Galactic O star spectroscopic survey aims at being complete up to B < 13
~1500 stars
* Spectral types
R ~ 2500 SNR ~ 300 3900 – 5100 A
* Binary detection Multi-epoch
2007 - xxx
OSN - 1.5mCAHA - 3.5m ISIS@WHT - 4.2m
Long-slit spectroscopy
Telescopes/instruments
Future
~ 50% of the survey is still missing – depends of TAC decission in next semesters
Exploring the Local Group massive star content
Milky Way
Science with the optical telescopes at CAHA & ORM
FIES@NOT - 2.5m R =23000, 46000 (3900-7000 A)
Telescopes/instruments
Future
~ 98% of the survey is complete but a couple of observing runs (2x4 nights) will allow to increase the number of detected binaries
NOT future !!!
+ HERMES@MERCATOR - 1.2m + CAFE@CAHA - 2.2m
The IACOB project (PI. Simón-Díaz)
* Line-broadening in OB stars
* Quantitative spectroscopic analyses
* Abundances in OB-type stars
* Massive binary/multiple systems
R > 20000 SNR > 200 3900 – 7000 A Multi-epoch
IACOB survey: Northern OB-type stars with V<8 ~200 stars
2008 – 2012?
Exploring the Local Group massive star content
Milky Way
Science with the optical telescopes at CAHA & ORM
FIES@NOT - 2.5mHERMES@MERCATOR - 1.2m
Telescopes/instruments
Future
Requires long time-series observations
Observing campaings of ~ 1-2 weeks per semester during several years
The IACOB project (PI. Simón-Díaz)
* Line-broadening in OB stars
* Quantitative spectroscopic analyses
* Abundances in OB-type stars
* Massive binary/multiple systems
R > 20000 SNR > 200 3900 – 7000 A Multi-epoch
IACOB survey: Northern OB-type stars with V<8 ~200 stars
2008 – 2012? Also CAFE@CAHA - 2.2m ??
Exploring the Local Group massive star content
Milky Way
Science with the optical telescopes at CAHA & ORM
HERMES@MERCATOR - 1.2m R =85000 (3900-9000 A)
Telescopes/instruments
Future
~ 50% of the survey is complete (due to bad weather)
New proposal (4 nights) this semester
IACOB-sweG (PI. Negueruela)
IACOB supplemented with an extension
to the Gaia spectral range
Grid of Galactic standards
SpT: O4 – B9LC: V, IV, III, II, Ib, Iab, Ia
R > 20000 SNR > 100 3900 – 9000 A
2010-2012
Exploring the Local Group massive star content
Milky Way
Science with the optical telescopes at CAHA & ORM
IDS@INT - 2.5mISIS@WHT - 4.2mFIES@NOT - 2.5mHERMES@MERCATOR - 1.2m
Telescopes/instruments
Future
CAFÉ-BEANS (PI. Negueruela)
Proposal submitted recently to the CAHA guaranteed time
CAFE@CAHA - 2.2m
+ Detailed studies of massive binaries
previously detected by GOSSS & IACOB
R > 8000 (but better if R>15000)
SNR > 100
Multi-epoch (periods from a few hours to years)
Exploring the Local Group massive star content
Milky Way
Science with the optical telescopes at CAHA & ORM
WFC@INT - 2.5m
IDS@INT - 2.5mISIS@WHT - 4.2mFIES@NOT - 2.5mHERMES@MERCATOR - 1.2mCAFE@CAHA - 2.2m
Telescopes/instruments
Future
Spectroscopic follow up for Gaia blue massive stars in (reddened) OB associations in the Milky Way with WEAVE@WHT
+ Detect and characterize OB associations
(including metallicity via B-type stars)
R > 8000 SNR > 100 4000 - 5000 A (+H)
Combined with wide-field imagery (OB associations)
Exploring the Local Group massive star content
Milky Way
Science with the optical telescopes at CAHA & ORM
Spectroscopic follow-up for GAIA blue massive stars
- We will use WEAVE to obtain spectra of all the members of Galactic OB associations.
* The brightest members are already spectroscopically confirmed OB stars, for which high resolution spectroscopy and quantitative analysis is already underway.
* But Gaia will unveil new reddened members, for which it will provide approximate spectroscopic classification and accurate distance measurements
* Nearby Milky Way OB associations typically extend 1 squared degree across the sky (see seminal catalogs by Humphreys or Massey)
- Example: Cas OB6 and Aur OB2 have a population of ~400 and 800 candidate blue massive star (Massey et al. (1995)) with V between 8 and 18.
- Good quality high resolution spectra for all the brightest members can be achieved with one single WEAVE pointing.
- Gaia will undoubtfully add new OB stars and association candidates to current lists.
Notes provided by Miriam Garcia (IAC)
Exploring the Local Group massive star content
- Massey & Tompson (1991) classify 70 OB stars in Cyg OB2- Based on 2MASS photometry, Knödlseder (2000) suggests that Cyg OB
contains over 100 O stars (not just OB)- Comeron et al. (2002) downsize it to 90-100 O stars and Hanson (2003)
confirms Comeron et al. findings observing the brightest stars between B = 12.0 - 14.5
- Negueruela et al. (2008) find new O stars and evidence for differet ages or aletrnative evolutionary scenarios
Milky Way
Spectroscopic follow-up for GAIA blue massive stars
Science with the optical telescopes at CAHA & ORM
An example provided by Artemio Herrero (IAC)
Exploring the Local Group massive star content
Science with the optical telescopes at CAHA & ORM
Local Group galaxies (other than the MW)
B-Sgs as tracers of abundance gradients
Luminous stellar objects But not bright enough to be observed at high-resolution 4m-class telescopes are needed WHT4.2m R – texp – SNR + spectral range coverage compromise
Typical configuration:
ISIS 1.2 arcsec slit R1200B and R1200R (R~5000, 3900-4800 A + H) SNR=80 for V=17.5 star (3 x 3600s) Seeing < 1.0 Grey moon
2-3 stars per night !!!! Thanks to the dicroic
Exploring the Local Group massive star content
Science with the optical telescopes at CAHA & ORM
Local Group galaxies (other than the MW)
From Urbaneja et al. (2005)
Dots: HII regions from Vilchez et al. (1988)
Good science case ...
... but very inefficient instrumental configuration
+ needs already discovered candidates
B-Sgs as tracers of abundance gradients (how things were done in the past)
Exploring the Local Group massive star content
Science with the optical telescopes at CAHA & ORM
Local Group galaxies (other than the MW)
1 deg
M33
B-Sgs as tracers of 2D abundance distributions (how we do things now)
Exploring the Local Group massive star content
Science with the optical telescopes at CAHA & ORM
Local Group galaxies (other than the MW)
1 deg
M33
1) WFC@INT (U,B,V) 33x33 arcmin
> First selection of candidates (using appropiate photometric indicators) > Accurate astrometry
2) AF2/WYFFOS@WHT
> 20 arcmin effective diameter > 80-100 effective fibers (1.6 arcsec) > R1200B + R1200R (R=2500) > 4000 – 5000 A + H > 8.5h: SNR=40 (V=18), 75 (V=17) > Confirmation of candidates > B-Sgs: 2D abundance distribution
B-Sgs as tracers of 2D abundance distributions (how we do things now)
Exploring the Local Group massive star content
Science with the optical telescopes at CAHA & ORM
+ Detect luminous blue stars (B Sgs, O stars, LBV, WRs) + Characterize OB associations + Spectral types
+ Stellar & wind parameters+ Abundances in a evolutionary context+ 1D/2D abundance distributions+ Detailed studies of selected candidates
Local Group galaxies (other than the MW)
** OK with WFC + R=2500 **
OK to a first order, but** better if higher resolution **
But not only B-Sgs as tracers of 2D abundance distributions
Exploring the Local Group massive star content
Science with the optical telescopes at CAHA & ORM
Local Group galaxies (other than the MW)
How things could improve in the near future: WEAVE@WHT
AF2/WYFFOS@WHT
> 20 arcmin effective diameter> 80-100 effective fibers (1.6 arcsec)> R1200B + R1200R (R=2500)> 4000 – 5000 A + H> 8.5h: SNR=40 (V=18), 75 (V=17)
AF2/WYFFOS@WHT
> 2 degrees FoV> 800-1000 fibers (1.2 – 1.5
arcsec)> R=5000> 4000 – 9000 A
Exploring the Local Group massive star content
Science with the optical telescopes at CAHA & ORM
Massive stars in Local Group galaxies: science case for WEAVE
Resolved massive stars in Local Group galaxies: Complete census of the unreddened massive star content in the Local Group.
- We want to get spectral classifications for all massive star candidates in Northern Local Group galaxies up to V= 19.0
- The resulting spectral types will be used for studies of global populations and to design follow up spectroscopic studies with larger telescopes for the most interesting cases:
• The quantitative spectroscopic analysis of a comprehensive sample of massive stars across the Local Group will allow us to study their physics, evolution, winds and feedback as a function of environment.
• Massive stars can be used as tracers of metallicity.
Some notes by M. Garcia & A. Herrero (IAC)
Exploring the Local Group massive star content
Science with the optical telescopes at CAHA & ORM
Conclusions
• We can do many things regarding massive star in the Milky Way and other Local Group galaxies using optical facilities at CAHA and ORM
• Specially remarcable is the importance of the high-resolution spectrographs (+efficient pipelines) attached to 1-4m telescopes for the detailed studies of bright Galactic OB stars. Less pressure more chances to get time for the binary and variability projects (+ large surveys)
• Multi-object spectroscopy is really valuable for us (as for many other science cases), and WEAVE will be of great benefit for the study of massive star in the Milky Way and other Local Group Galaxies.
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