a panoramic hst infrared view of the galactic center q. d. wang, h. dong, d. calzetti (umass), a....
TRANSCRIPT
A Panoramic HST Infrared View ofthe Galactic Center
Q. D. Wang, H. Dong, D. Calzetti (UMass) , A. Cotera (SETI), S. Stolovy, M. Muno, J. Mauerhan, (Caltech/IPAC/JPL), C. C. Lang (U. of
Iowa), M. R. Morris, E. A. Mills (UCLA), G. Schneider (U. Arizona)
Q. Daniel Wang (UMass; [email protected])
• Please see also the posters by Hui (415.01) and Mills (416.10) et al. today.
• More information can be obtained at www.astro.umass.edu/~wqd/gcps/web/
Q. Daniel Wang (UMass; [email protected])
HST/NICMOS 1.90m Map of the Galactic Center
• Distance to the Galactic center: 26,000 light-year• Resolution: 0.025 light-year (0.2”)• 144 HST orbits, taken between Feb and June, 2008 144X4X4=2304 images for each of the two wavelength filters
39’ (300 light-year)
15’ (115 light-year)
Sgr A*
Arches cluster
Quintuplet cluster
l
b
Foreground dusty clouds
Q. Daniel Wang (UMass; [email protected])
HST/NICMOS 1.87m Map of the Galactic Center
• The 1.9m filter is sensitive to the stellar continuum emission.• The 1.87m filter covers the P line.• Subtracting the 1.9m map from the 1.87m map adaptively.
A net P line emission map (see the poster by Dong et al.; 415.01) .
Sgr A*
Arches cluster
Quintuplet cluster
Arched HII filaments
Sickle HII region
Q. Daniel Wang (UMass; [email protected])
Net Pα Map of the Galactic Center
Why do we need the HST?• Excellent imaging stability• Only observable from the space• Little background due to the Earth’s warm atmosphere
Q. Daniel Wang (UMass; [email protected])
Map of Pα + stellar continuum: Preliminary Results
• ~0.6 million stars, resolving ~65% of the total stellar light observed.
• ~300 stars show enhanced Pα emission (green dots).• ~2/3 of them are located outside the three known clusters.• 13 have been followed up spectroscopically, confirming that they
are indeed massive stars a new population of massive stars.
• Ionized gas features resolved into arrays of organized linear filaments strong local magnetic fields.
Q. Daniel Wang (UMass; [email protected])
Sickle HII Region
Red: radio continuum Green: P Blue: 1.9m
Detailed structure of ionized gas pillars sculpted by the intense radiation and wind from the Quintuplet cluster.
But magnetic field may also play a critical role (see the poster by Mills et al.; 416.10).
Q. Daniel Wang (UMass; [email protected])
Red: 8m (IRAC) Green: P Blue: 1.9m
• Ionized gas around the supermassive black hole is confined to a spiral embedded in a circumnuclear dusty torus.
• Evidence for ionized gas outflows from this torus.
Nuclear Spiral/Torus
Sgr A*
Q. Daniel Wang (UMass; [email protected])
Summery• We have produced an unprecedented high-resolution
infrared panorama of the Galactic center. Initial results:– Discovery of a new population of very massive stars in
relative isolation and with strong winds.– Fine filamentary structures of ionized diffuse gas
indicating profound influence of local strong magnetic field.
– Detections of compact nebulae, tracing various stages of massive star evolution
• We aim to understand the formation modes of massive stars and their interplay with the extreme environment in galactic nuclei. • Please see posters by Dong (415.01) and Mills (416.10) et al. today
• More information available at www.astro.umass.edu/~wqd/gcps/web/
• The research is supported by NASA/STScI
Q. Daniel Wang (UMass; [email protected])
GC2009 Workshop: The window to nuclear environment of disk galaxies
• Place: Shanghai • Dates: October 19-23
– a 4.5 full-day science program, including “min-debates” focusing on key unsolved issues.
– A half-day tour (a small ancient town, the famous Bund, a banquet dinner on a boat touring the Huang-Pu river).
• http://www.shao.ac.cn/gc2009/
Q. Daniel Wang (Umass) [email protected])
Topics• physics of the accretion flow around SMBHs, including the
mechanism of the flaring activity in Sgr A*• high energy phenomena -- gamma rays and cosmic rays • star formation in circumnuclear regions and the distinction
from "normal" star formation environment • stellar dynamics around SMBHs • population and distribution of compact objects around
SMBHs • stellar and gaseous contents in the nuclear and
circumnuclear regions and the fueling of SMBHs • SMBH feedback effects on the nuclear and circumnuclear
environment• interplay between stars and the interstellar medium• magnetic field and its role in regulating the gas dynamics• fundamental physics at the Galactic Center (e.g., dark
matter annihilation and GR effects) • formation and evolution of SMBHs