exploring the local group massive star content with 2-4m telescopes at orm and caha

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


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


Signal-to-noise ratio


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)


Spectral range coverage



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


Milky Way


FIES@NOT - 2.5m R =23000, 46000 (3900-7000 A)


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?


Milky Way


FIES@NOT - 2.5mHERMES@MERCATOR - 1.2m


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 ??


Milky Way


HERMES@MERCATOR - 1.2m R =85000 (3900-9000 A)


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


Milky Way


IDS@INT - 2.5mISIS@WHT - 4.2mFIES@NOT - 2.5mHERMES@MERCATOR - 1.2m


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)


Milky Way


WFC@INT - 2.5m

IDS@INT - 2.5mISIS@WHT - 4.2mFIES@NOT - 2.5mHERMES@MERCATOR - 1.2mCAFE@CAHA - 2.2m


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)


Milky Way


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)


- 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


An example provided by Artemio Herrero (IAC)




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




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)




1 deg

M33

B-Sgs as tracers of 2D abundance distributions (how we do things now)




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)



+ 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


** 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




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



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)



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.

exploring the local group massive star content with 2-4m telescopes at orm and caha

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