1. Red Supergiants in the Inner Galaxy: an infrared spectroscopic search
Maria Messineo
University of Science and Technology of China
(USTC -Hefei)
Coauthors:
Don Figer (RIT) Karl Menten (MPIfR)
Rolf Kudritzki (IfA) Rosie Chen (MPIfR)
Valentin Ivanov (ESO) Zhu Quingfeng (USTC)
Special thanks to:
Harm Habing (Leiden), Ed Churchwell (Wisconsin-Madison Univ.), Ben Davies (LJMU)
Canberra,

2. Red Supergiants
What: Stars > 8 Msun
Fate: BH or NS
initial mass, Z, Winds, rotation, B
Where: in Clusters/Associations
isolated ?

3. Massive stars
Why: Galactic structure (e.g. spiral arms)
ISM-metallicity
ISM-shapers
Distance indicators

4. Credit: Robert Hurt, IPAC; Bill Saxton, NRAO/AUI/NSF
Norma
Perseus
5 RSGCs
Sagittarius
1 RSGCs
Scutum-crux
Based on: GLIMPSE & Bessel results

5. A infrared stellar cluster rich in RSGs: RSGC1
GAP
Figer et al. (2006)
Images: 2MASS

6. Color selection 1 Q1 =(J−H)−1.8×(H−Ks); Q2 =(J−Ks)−2.69×(K−[8.0])
Messineo M, Menten K.M., Churchwell E., Habing H., 2012 A&A, 537,10

7. Color selection 2 Q1 =(J−H)−1.8×(H−Ks); Q2 =(J−Ks)−2.69×(K−[8.0])
GLIMPSE NorthI-2MASS catalog
Ks < 7 ~9000 stars
Aks > 0.4 mag
Mbol < -6.1 for 4 kpc
i.e. Ks< 4+Aks
~130 stars of which 94 were spectroscopically observed
Messineo M., Zhu Q., Menten K.M., Ivanov V.D., Figer D.F., Kudritzki R.P., Chen C.-H. R. (2016, ApJ, 822, 5)

8. Water index is defined as in Blum et al. 2003, ApJ, 597,323

9. (l,b) distribution Targets Known: Skiff & Negueruela et al &
Figer et al &
Davies et al.
Messineo M., Zhu Q., Menten K.M., Ivanov V.D., Figer D.F., Kudritzki R.P., Chen C.-H. R. (2016, ApJ, 822, 5)

10. Current distances from clump stars
2MASS/UKIDSS K vs J-K diagrams

11. RESULTS
Observed 94 targets (10 < l < 65 deg, |b|<1deg)
58 of them are spectroscopic RSGs
(no water and EW(CO) > 45 Angstroms).
for 68 of them distances are obtained with clump stars.
Heliocentric distances: 3.6 to 8.6 kpc.
Galactocentric distances: 2.5 to 7.6 kpc.
Luminosities: 3.2 x 10^4 to 1.3 x 10^5 Lsun
This is an increase of at least +25% (64) in the number of previously known RSGs in the searched area.

12. Spatial distribution of the sample of RSGs (red dots)
Arms: Lazio & Cordes 2001
46% RSGs
Free-free

13. Luminosities Ekstroem et al 2012 Chieffi et al. 2013
Messineo M., Zhu Q., Menten K.M., Ivanov V.D., Figer D.F., Kudritzki R.P., Chen C.-H. R. (2016, ApJ, submitted)

14. Future
Observed – To be observed

15. THANK YOU
to all of you