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ATLASGAL: Galaxy-wide Sample of Embedded Massive Stars
First results from A
F. Schuller, S. Bontemps, L. Bronf
MPG: Schuller (PI, now: ESO),
Menten,
Wyrowski, Csengeri,
(MPIfR)
M.Urquhart
Walmsley,
F. Wyrowski
and the A
James
James Urquhart
Beuther, Henning, Linz (MPIA), Schilke (Cologne)
ESO: Walmsley (co-PI), Bontemps, Cesaroni, Deharveng, Herpin, Lefloch, Molinari, Motte, Minier,
Nyman, Reveret, Risacher, Russeil, Schneider,
Zavagno- MPIfR Bonn
´ Testi,
´
Fred
eric
Schuller
First results
Chile: Bronfman (co-PI), Contreras, Garay, Mardones
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
1
ATLASGAL: Galaxy-wide Sample of Embedded Massive Stars
Talk Outline
•
•
•
Overview of the ATLASGAL Survey
•
Compact Source Catalogues
•
Follow-up Programmes
•
Database
Identification of Massive Star Forming Clumps
•
Results
•
Further Work
Summary
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
2
Overview of ATLASGAL Survey
Survey Summary
•
•
•
•
APEX 870 μm continuum survey of the inner Galactic plane (280° < l < 60°, |b| < 1.5°)
LABOCA: Large APEX BOlometer CAmera (MPIfR) — 295 element bolometer camera
Covers 420 sq. degrees with ang. resolution of ~19″ and sensitivity of ~60 mJy/beam
Covers ~60% of the Galactic disk but almost all of the region within the Solar Circle
•
covers ~90% of all dense molecular gas in the Galaxy
15 kpc
Temperature = 20 ± 5 K
~1,000 M⊙◉☉
GC
5σ = 300 mJy
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
3
Overview of the ATLASGAL Survey
Submillimetre Emission: Structure of the Dust
10% of the Survey
Diffuse
Filaments
James Urquhart
Compact
Clumps
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
4
Compact
Source
Catalogues
sed
survey
of the
inner Galactic Plane at 870 µm, wit
Source Extraction
CA
(295-bolometer array) at APEX (beam: 1900 )
ssive
starSource
formation
throughout
the Galaxy
• GaussClump
Source Catalogue (GCSC)
• Compact
Catalogue (CSC)
• produced using Multi-resolution filtering
• produced using SExtractor on the
-stellar
initial
mass
function
down
to a few M
(wavelets) to remove extended emission
reduced maps
GaussClump
ge scale
the cold• and
ISM
• Identifiedstructure
~ 10,000 sources of
— Contreras
Full catalogue consists of ~ 10,000
et al., 2013 & Urquhart et al., 2014
sources — Csengeri et al., 2014
IRAS 12+60+100 µm, |l| ⇥ 90 , |b| ⇥ 10
ATLASGAL
l = -60
l = -80
l = +60
•
Both catalogues have identified a similar number of
sources and have a similar level of completeness
(~99% above 6σ)
2
The CSC and GC are very complementary:
ing
80 ⇥ l ⇥ 60 , |b| ⇥ 1.5 , r.m.s. ⇥ 50 mJy/beam
⇧ 420 deg , 5⇥ detection :
•
the former better probing the whole clump structure
0.5•• M
atlatter
500
pc,
M associated
at 3 kpc,
⇤100 M at 8 kpc
while the
probing
the 20
gas directly
with
star formation
2 - Di Francesco et al. 2008
ifetime
of
SCUBA
:
30
deg
James Urquhart
5
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
Compact Source Catalogues
Source Extraction: SExtractor Example
19.2
−0.08
−0.17
Latitude
−0.25
9.7
−0.33
−0.42
6.5
−0.50
0.177
>5σ
3.3
Jy/Beam
4.71977
0.0
12.8
Contreras et al., 2013, A&A, 549, 45
16.0
<5σ
−0.58
0.1
20.17
James Urquhart
20.00
19.83
19.67
Longitude
Center: Longitude 19.81 Latitude −0.32
19.50
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
6
Compact Source Catalogues
Csengeri et al. 2013, A&A
Galactic Distribution
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
7
Follow-up Programmes
Molecular Line
•
Molecular line obs. are an important part of
the follow-up programmes
•
radial velocities + Gal. Rotation curve
•
•
distances
providing information on the gas kinematics,
temperature and chemistry
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
8
Follow-up Programmes
•
Wienen et al. 2012, A&A, 544, 146
Molecular Line
Molecular line obs. are an important part of
the follow-up programmes
•
radial velocities + Gal. Rotation curve
•
•
distances
providing information on the gas kinematics,
temperature and chemistry
NH3 (1,1) to (3,3) observations towards
~2,000 sources
James Urquhart
Urquhart et al. 2011, MNRAS, 418, 1689
•
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
8
Follow-up Programmes
Molecular Line
•
Molecular line obs. are an important part of
the follow-up programmes
•
radial velocities + Gal. Rotation curve
•
•
Mopra 3mm Survey
x5
distances
providing information on the gas kinematics,
temperature and chemistry
•
NH3 (1,1) to (3,3) observations towards
~2,000 sources
•
Broadband molecular line follow-ups at 3mm
(Mopra and IRAM 30-m) and 1mm (APEX)
Wyrowski et al. 2015, A&A, In prep.
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
8
Follow-up Programmes
Molecular Line
•
Molecular line obs. are an important part of
the follow-up programmes
•
radial velocities + Gal. Rotation curve
•
•
MALT90 — Protostellar Source
distances
providing information on the gas kinematics,
temperature and chemistry
•
NH3 (1,1) to (3,3) observations towards
~2,000 sources
•
Broadband molecular line follow-ups at 3mm
(Mopra and IRAM 30-m) and 1mm (APEX)
•
Multi-transition mapping by MALT90 (Mopra)
and SuperMalt(APEX)
Jackson et al., 2013, PASA, 30, 57
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
8
Follow-up Programmes
Molecular Line
•
Molecular line obs. are an important part of
the follow-up programmes
•
radial velocities + Gal. Rotation curve
•
•
distances
providing information on the gas kinematics,
temperature and chemistry
•
NH3 (1,1) to (3,3) observations towards
~2,000 sources
•
Broadband molecular line follow-ups at 3mm
(Mopra and IRAM 30-m) and 1mm (APEX)
•
Multi-transition mapping by MALT90 (Mopra)
and SuperMalt(APEX)
•
13CO
obtained from GRS, CHIMPS, MopraCO
and SEDIGISM
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
8
Follow-up Programmes
Molecular Line
13CO
•
(2-1) — VLSR = -50 to -43 km/s
Molecular line obs. are an important part of
•
•
distances
providing information on the gas kinematics,
temperature and chemistry
•
NH3 (1,1) to (3,3) observations towards
Galactic Longitude
~2,000 sources
Broadband molecular line follow-ups at 3mm
Galactic Latitude
•
ATLASGAL
(Mopra and IRAM 30-m) and 1mm (APEX)
•
Multi-transition mapping by MALT90 (Mopra)
and SuperMalt(APEX)
•
13CO
obtained from GRS, CHIMPS, MopraCO
MPIfR PI: Urquhart
radial velocities + Gal. Rotation curve
SEDIGISM: Structure, Excitation, and Dynamics
of the Inner Galactic Interstellar Medium
•
Galactic Latitude
the follow-up programmes
and SEDIGISM
Galactic Longitude
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
8
ATLASGAL Database
Front Page
http://atlasgal.mpifr-bonn.mpg.de/cgi-bin/ATLASGAL_DATABASE.cgi
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
9
ATLASGAL Database
Source Details
http://atlasgal.mpifr-bonn.mpg.de/cgi-bin/ATLASGAL_DATABASE.cgi
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
10
ATLASGAL Database
Complementary Datasets
http://atlasgal.mpifr-bonn.mpg.de/cgi-bin/ATLASGAL_DATABASE.cgi
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
11
ATLASGAL: Galaxy-wide Sample of Embedded Massive Stars
Talk Outline
•
•
•
Overview of the ATLASGAL Survey
•
Compact Source Catalogues
•
Follow-up Programmes
•
Database
Identification of Massive Star Forming Clumps
•
Results
•
Further Work
Summary
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
12
Identification of Massive Star Forming Clumps
Courtesy of Cormac Purcell
Evolutionary Sequence for Massive Stars
•
Previous studies have focused on specific tracers to select samples of study
massive star formation (e.g., masers, far- and mid-infrared, radio continuum).
•
•
tend to isolate a specific stage and exclude the earliest pre-stellar stages
Ideally we want an unbiased view of all evolutionary stages that covers a large
fraction of the Galaxy in order to provide reliable statistical results
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
13
Identification of Massive Star Forming Clumps
Evolutionary Sequence for Massive Stars
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
14
Identification of Massive Star Forming Clumps
Evolutionary Sequence for Massive Stars
Methanol Masers
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
14
Identification of Massive Star Forming Clumps
Evolutionary Sequence for Massive Stars
Methanol Masers
James Urquhart
MYSOs
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
14
Identification of Massive Star Forming Clumps
Evolutionary Sequence for Massive Stars
Methanol Masers
James Urquhart
MYSOs
Compact HII regions
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
14
Identification of Massive Star Forming Clumps
Evolutionary Sequence
•
Submillimetre dust emission
•
•
Courtesy of Cormac Purcell
Galactic Plane Surveys
ATLASGAL, JPS & SaSSy
CORNISH 5 GHz VLA Continuum survey
— UCHII regions
•
The Red MSX Source Survey — MYSOs
+ UCHII regions
•
•
The Methanol Multibeam (MMB) Survey
Identified ~1700 embedded sources
matched to 1300 dust massive star
forming clumps
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
15
Results
Clump Structure
•
•
•
Massive star formation is strongly correlated with
regions of highest column density found towards
the centre of their host clump
The structure of the MSF clumps is significantly
different from the general population
•
Angular Offset
1/2 Beam Width
more spherical and centrally condensed
There is no difference between these parameters
for any of the subsamples
•
the structure of the host clump changes little during the
formation process
Elongation (σmaj/σmin)
James Urquhart
Compactness (Sint/Speak)
Median = 1.38
Median = 4.7
Median = 1.53
Median = 7.4
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
16
Results
Column Density Distribution
10.0
Source Counts
1000.0
100.0
10.0
1.0
0.1
21.5
Surface Density (g cm−2)
0.1
1.0
Fraction of Embedded Massive Stars
Surface Density (g cm−2)
0.1
1.0
22.0
22.5
23.0
23.5
24.0
Log[Peak H2 Column Density (cm−2)]
24.5
10.0
1.0
0.8
0.6
0.4
0.2
0.0
21.5
22.0
22.5
23.0
23.5
24.0
−2
Log[Peak H2 Column Density (cm )]
•
There are very few high column density clumps outside the Galactic Centre
region not already associated with massive star formation
•
Supports a fast star formation timescale with the pre-stellar phase for the most
massive clumps being so short it may be effectively unobservable
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
24.5
17
Results
Mottram et al. in prep.
Galactic Distribution
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
18
Results
Virial Parameter-Clump Mass Relation
Methanol Masers
MYSOs
HII Regions
Multi-phase
Virial Ratio (Mvir/Mclump)
10.00
1.00
0.10
0.01
101
102
103
104
Clump Mass (M O• )
105
• Nearly all MSF clumps are unstable to global gravitational collapse without the
presence of significant magnetic support
• However, even if strong magnetic fields are present they are unable to prevent
more local regions collapsing since they are all forming massive stars
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
19
Results
Luminosity-Mass Relation
•
MYSOs and HII regions are at similar stages in their evolutions but methanol
masers are genuinely younger
•
Estimated the SFE for Galaxy-wide sample of embedded massive stars
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
20
Further Work
3D Galactic Distribution of Dense Material
• The ATLASGAL clumps
associated with MSF amount to
~20% of the sample
• Work is already underway to
extract molecular line emission
towards the rest of the population
• 80% complete
• Using a friend-of-friends
algorithm to identify complexes;
this will significantly reduce the
number of distances required
• We find ~200 complexes that are
associated with ~75% of all
clumps
• The largest 50 complexes are
associated with ~50% of all
sources
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
21
Further Work
Role of the Spiral Arms and Environment
GLIMPSE Bubble + ATLASGAL Dust Emission
Green 8 μm, Red 24 μm and Blue 870 μm
APEX SEDIGISM — MPIfR PI Urquhart
•
•
With reliable distances we can map the 3d distribution of dense material and MSFR across the Galaxy
Link the dense gas with the large scale structure and kinematics of filaments and GMC and larger
scale complex
•
•
•
•
Clump formation efficiency (Mdense/Mcloud) and Star formation efficiency (Lbol/Mdense)
Evaluate the role of the spiral arms and environment
Investigated formation mechanism of clumps and their filamentary nature
Use the different environmental conditions to probe SF in more distant galaxies
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
22
ATLASGAL: Galaxy-wide Sample of Embedded Massive Stars
Summary
•
•
The ATLASGAL survey provides a complete inventory of dense molecular clumps
located throughout the inner Galactic disk → 10,000 sources
Cross-matching these sources with other MSF surveys we have identified ~1300
MSF clumps (20% of the total sample) including most important embedded phases
•
These will be used to investigate:
•
the evolutionary sequence of massive stars and estimate the statistical lifetime of each
stage and evaluate initial conditions and environment in the star formation process
•
•
star formation as a function of clump mass, luminosity and Galactic location
Identify interesting objects for future follow-up with ALMA and the JVLA
•
e.g., massive protostellar clusters and transition objects
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
23
ATLASGAL: Galaxy-wide Sample of Embedded Massive Stars
Summary
•
•
The ATLASGAL survey provides a complete inventory of dense molecular clumps
located throughout the inner Galactic disk → 10,000 sources
Cross-matching these sources with other MSF surveys we have identified ~1300
MSF clumps (20% of the total sample) including most important embedded phases
•
These will be used to investigate:
•
the evolutionary sequence of massive stars and estimate the statistical lifetime of each
stage and evaluate initial conditions and environment in the star formation process
•
•
star formation as a function of clump mass, luminosity and Galactic location
Identify interesting objects for future follow-up with ALMA and the JVLA
•
e.g., massive protostellar clusters and transition objects
Atacama Large Millimetre Array
James Urquhart
Milky Way Astrophysics from Wide-Field Surveys, RAS London, March 30, 2015
23