Transcript AAS Plenary Talk, May 2011 - National Radio Astronomy Observatory

Early science with the Expanded Very Large Array
C. Carilli and R. Perley (NRAO)
• Brief intro: impact and evolution
• Early science: highlights from the ApJL special issue
 Broad impact: few examples
 Molecular gas in early galaxies: tracing fuel for star
formation over cosmic time
• Project description and status
Public and professional impact of astronomical
facilities (Courtesy M. Garrett)
Peer reviewed papers 2000-2010
VLA
Google Hits
VLA: a facility for everyone
• VLA receives ~ 500 proposals per year
• NRAO PST has 4000 registered users
Problem: VLA is 30yrs old
Solution: the Expanded Very Large Array!
Build on existing infrastructure, replace all electronics
(correlator, Rx, IF, M/C) => multiply ten-fold the VLA’s
observational capabilities
• 80x Bandwidth (8 GHz, full stokes), with 16384 channels
• Full frequency coverage from 1 to 50 GHz
• 10x continuum sensitivity (<1uJy)
• 40mas resolution at 43GHz (7mm)
• Well on way to completion end of 2012
EVLA + ALMA represent > order of magnitude improvement
in observational capabilities from 1 GHz to 1 THz
Early science with the EVLA: ApJL special issue
• Started in March, 2010, w. up to 2GHz BW
• Only compact configurations and (mostly) higher frequencies
• Typically broad program: 36 articles spanning A2010 key
science panels
Planetary Systems and Star Formation
The Galactic Neighborhood
 EVLA observations of the Barnard 5 star forming cloud: embedded
filaments revealed (Pineda)
 The mm colors of a young binary disk system in the Orion Nebular
Cluster (Ricci)
 Microwave observations of edge-on protoplanetary disks (Melis)
 First results from a 1.3cm EVLA survey of massive protostellar
objects (Brogan)
 Unveiling the sources of heating in the vicinity of the Orion-KL hot
core as traced by High-J rotational transitions of NH3 (Goddi)
 EVLA continuum observations of massive protostars (Hofner)
 Searching for new hypercompact HII regions (Sanchez)
 Deep radio continuum imaging of the dwarf irregular IC10: tracing
star formation and magnetic fields (Heesen)
 Complex radio spectral energy distributions in luminous IR galaxies
(Leroy)
 SHEILD: The survey of HI in extremely low mass dwarfs (Cannon)
 EVLA detection of 44.1GHz class I methanol masers in Sgr A
(Philstrom)
 EVLA observations of Galactic supernova remnants (Bhatnagar)
 Discovery of a nearby galaxy discovered in the Arecibo zone of
avoidance (McIntyre)
 EVLA detection of 44.1GHz class I methanol masers in Sgr A
(Philstrom)
Stars and Stellar Evolution
Gone with the wind: EVLA observations of the nebula around
G79.29+0.46 (Umana)
 A pilot imaging line survey of AGB stars RW Lmi and IK Tau
(Claussen)
 IRAS 18113-2503: the PN water fountain with the fastest jet? (Gomez)
 EVLA observations of the classical Nova V1723 Aquilae (Krauss)
 A deep radio survey of hard state and quiescent black hole binaries
(Miller-Jones)
Auroral emission from stars: the case of CU Virginis (Trigilio)
Galaxies through cosmic time (CO!)
 EVLA observations of a proto-cluster of molecular gas rich galaxies
at z=4.05 (Carilli )
CO line emission from z=6 quasar host galaxies (Wang)
 Imaging the molecular Einstein ring at z=3.9 (Lestrade)
 Extended molecular gas reservoirs in z=3.4 submm galaxies
(Riechers)
 CO in z = 2 quasar host galaxies: no evidence for extended gas
reservoirs (Riechers)
PSSF: subsonic cloud fragmentation in low mass star forming
region Bernard 5
Pineda ea
0.5km/s
σ< 50 m/s
<0.2km/s
λJ
YSO
YSO
GBT NH3
EVLA
High spectral/spatial res. imaging of NH3 => densities > 104 cm-3
• GBT: clearly-bounded region of suppressed turbulence in molecular
dark cloud: σ falls from 0.5 km/s to < 0.2km/s
• EVLA: filament of dense gas, substructures < 1000AU, σ < 50 m/s!
• Separation YSO and starless core ~ Jeans length
SSE: 18 to 40 GHz imaging line survey of AGB stars
RW LMi
HC3N
8000AU
Claussen ea
SiS
AGB outflows are key to ISM
molecule and dust enrichment (Mass
loss rate ~ 10-4 Mo/yr)
• Pilot study w. new 36 GHz band:
HC3N reveals multiple shells tracing
episodic circumstellar envelope
evolution, on road to PNe
• Shell radii ~ 800 to 4000 AU, vexp ~
13 km/s => age date outbursts over
last 1200 yrs
• SiS emission much more compact
GN: IC10 = laboratory for studying star formation
in dwarf galaxies on 50pc scales
radio contours + Hα
Heesen ea
EVLA: wide-band allows total intensity + spectral index imaging
• 4-8 GHz emission traces Hα closely ~ ½ thermal, ½ synchrotron
• SFR (radio/Hα) suggests ~ ½ of CRs lost in outflow
• B fields confine cosmic rays in ‘superbubble’
GTCT: molecular gas in early galaxies and the dense gas
history of the Universe
GN20 z=4
submm galaxy
Wilson et al.
CO image of
‘Antennae’ merging
galaxies
C
O
HST/CO/SUBMM
• cm/mm reveal the dust-obscured, earliest, most active
phases of star formation in galaxies
• cm/mm reveal the cool gas that fuels star formation
cm  submm astronomical probes of galaxy formation
100 Mo yr-1 at z=5
• Low J molecular lines: total gas
mass, dynamics
• Synch. + Free-Free = star form.
(GBT)
• High J molecular lines: gas
excitation, physical conditions
• Dust continuum = star form.
• Atomic fine structure lines:
ISM gas coolant
Massive galaxy and SMBH formation at z~6: Quasar hosts
at tuniv<1Gyr
SDSS1148+5251
z=6.42
FIR
HyLIRG
Wang sample 35
z>5.7 quasars
MBH ~ 109 Mo
• 30% of z>2 quasars have S250 > 2mJy
• LFIR ~ 0.3 to 1.3 x1013 Lo => SFR ~ 103 Mo/yr
• Coeval, rapid formation of SMBH and massive host
galaxy in early Universe
Molecular gas = fuel for star formation
11 CO detections in z~6 quasars with EVLA, PdBI
EVLA CO 2-1
z=6.2
200uJy
1”
z=5.8
Wang ea
• M(H2) ~ 0.7 to 3 x1010
(X/0.8) Mo
• Very early enrichment of
dust and metals
• Imaging: multiple CO
sources => gas rich
mergers?
CO excitation: Dense, warm gas, thermally excited to 6-5
230GHz
691GHz
starburst nucleus
Milky
Way
• LVG model => Tk > 50K, nH2 = 2x104 cm-3
• Galactic Molecular Clouds (50pc): nH2~ 102 to 103 cm-3
• GMC star forming cores (~1pc): nH2~ 104 cm-3
LFIR vs L’(CO): Star Formation Law at tuniv < 1Gyr
‘Integrated Kennicutt-Schmidt relation’
•Further circumstantial
evidence for star formation
SFR
•Gas consumption time
(Mgas/SFR) decreases with SFR
1e3 Mo/yr
FIR ~ 1010 Lo/yr => tc > 108yr
FIR ~ 1013 Lo/yr => tc < 107yr
Index=1.5
MW
1e11 Mo
Mgas
Imaging => dynamics => weighing the first galaxies
0.15” TB ~ 25K
z=6.42
Plateau de Bure
CO3-2 VLA
-150 km/s
7kpc
1” ~ 5.5kpc
+
+150 km/s
Riechers ea
 Size ~ 6 kpc, with two peaks ~ 2kpc separation
 Dynamical mass (r < 3kpc) ~ 6 x1010 Mo
 M(H2)/Mdyn ~ 0.3
Break-down of MBH – Mbulge relation at high z
Wang ea
• <MBH/Mbulge> ~ 15
higher at z>4 => Black
holes form first?
• CO/dust imaging is only
probe host galaxy to date
• Caveats:
Need better CO imaging
Bias for optically
selected quasars?
MBH = 0.0014 Mbulge => causal connect between BH and gal. formation
z=4: GN20 molecule-rich proto-cluster
CO 2-1 in 3 submm galaxies within 30”, 256 MHz
0.7mJy
0.3mJy
sBzK z=1.5
1000 km/s
z=4.055
• 19 z~4 LBGs
• 3 SMGs at z ~ 4.05
LFIR ~ 1013 Lo
SFR ~ 103 Mo/yr
M(H2) ~ 1011 Mo
 Clustered, massive
galaxy formation at
tuniv ~ 1.6Gyr
4.056
0.4mJy
4.051
Daddi ea; Carilli ea
Spectroscopic imaging: A detailed look at
massive galaxy formation in the early Universe
CO2-1
+250 km/s
+
1”
30kpc
-250 km/s
HST/CO/SUBMM
+
GN20: Obscured starburst at z=4.0
• Rotating, gravitationally disturbed
disk ~ 10 kpc
• Mdyn (r<5kpc) ~ 3x1011 Mo ~ Mgas
+ M*
‘Serendipitous’ detection of CO in
same field/band from ‘typical’ star
forming galaxy at z=1.5 (‘sBzK
galaxy’)
z=1.5
EVLA
CO 1-0
• SFR ≤ 100 Mo/yr
• HST/Hα/CO imaging => ‘clumpy,
rotating disk’ ~ 10kpc (Genzel, Tacconi,
Daddi)
Daddi; Aravena
PdBI
CO2-1
• Systematically detected in CO: Mgas
> 1010 Mo => massive gas reservoir
w/o extreme starburst
• Good news for EVLA: common ~ 5
arcmin-2 ~ 100x SMGs
400 km/s
Closer to Milky Way-type gas conditions
LFIR/L’CO
HyLIRG
1.5
1
sBzK
Dannerbauer, Aravena ea
 Lower CO excitation: low J observations are key!
 FIR/L’CO: Gas consumption timescales ~ few x108 yrs
=> Secular disk galaxy formation during epoch of galaxy assembly
Gas dominated disks
Fgas = MH2/(M*+MH2)
Mgas ≥ Mstars => fundamental change in galaxy properties during
peak epoch of cosmic star formation (z~2)
EVLA: Large cosmic volume
blind searches for molecular gas
• 19 to 27 GHz => CO1-0 at z=3.2
to 5.0, 1 beam = 104 cMpc3
• Every few hour EVLA
observation at > 20 GHz will
discover new galaxies in CO!
M* > 1010 Mo
sBzK
BX/BM
BX/BM
Geach ea.; Daddi ea; Carilli ea.; Tacconi ea.
Dense gas history of the Universe
H2
Bouwens ea
EVLA is poised to trace the
fuel for star formation over
cosmic time
SF Law
LIR ~ SFR
[Obreschkow ea; Del P. Lagos ea.;
Bauermeister ea; Carilli ea]
LCO ~ Mgas
National Radio Astronomy Observatory
The Expanded Very Large Array:
What It Can Give You,
and
How to Get It
Rick Perley
EVLA Project Scientist
National Radio Astronomy Observatory
EVLA Project Overview
• The Expanded Very Large Array is a major upgrade of the
Very Large Array.
• The fundamental goal is to improve all the observational
capabilities of the VLA -- except spatial resolution -- by at
least an order of magnitude
• The project will be completed by the end of 2012
• The EVLA is available now with unprecedented new
capabilities.
Key EVLA Capability Goals
• Full frequency coverage from 1 to 50 GHz.
• Up to 8 GHz instantaneous bandwidth, per polarization
• New correlator with 8 GHz/polarization capability
– Unprecedented flexibility in matching resources to enable science goals.
– Many special modes for special applications.
• Full Polarization standard for all correlator setups
• <3 mJy/beam (1-s, 1-Hr) continuum sensitivity at most bands.
• <1 mJy/beam (1-s, 1-Hr, 1-km/sec) line sensitivity at most bands.
• Noise-limited, full-field imaging in all Stokes parameters for most
observational fields.
EVLA-VLA Capabilities Comparison
The EVLA’s performance will be vastly better than the VLA’s:
Parameter
VLA
EVLA
Factor
Current
Point Source Cont. Sensitivity
(1-s,12hr.)
10 mJy
1 mJy
10
2 mJy
0.1 GHz
8 GHz
80
2 GHz
# of frequency channels at
max. BW
16
16,384
1024
4096
Maximum number of freq.
channels
512
4,194,304
8192
16,384
Coarsest frequency resolution
50 MHz
2 MHz
25
2 MHz
Finest frequency resolution
381 Hz
0.12 Hz
3180
.12 kHz
# of full-polarization spectral
windows
2
64
32
16
22%
100%
5
100%
Maximum BW in each
polarization
(Log) Frequency Coverage (1
– 50 GHz)
EVLA Resolution
• EVLA is a reconfigurable array
• The resolution, in arcseconds is given in the table:
Frequency Band
Configuration
1-2 2-4 4-8
812
12-18
1827
2740
40-50
Dates
Available
A 1.3 .65 .33 .23
.13
.089 .059 .043
June 10 – Sept 12,
2011
Mid-Sep – mid-Dec,
2012
B 4.3 2.1 1.0 .73
.42
.28
May 25 – mid-Aug,
2012
.19
.14
• The
angular
which .95
can be.63
imaged
configuration
is
7.0 3.5
2.5size1.4
.47in anyJan
27 – Apr 23,
C 14largest
about 25 times the listed resolution.
2012
• If larger-scale structure imaging is required, observations in a smaller
46 23 12are8.1
4.6 3.1 2.1 1.5 Sep 30 – Dec 27, 2011
needed.
Dconfiguration
EVLA Sensitivity (rms in 1 Hour)
EVLA Status
• All 28 antennas are now converted to EVLA standards.
• Installation of new wideband receivers now complete at:
–
–
–
–
•
•
•
•
4 – 8 GHz (C-Band)
18 – 27 GHz (K-Band)
27 – 40 GHz (Ka-Band)
40 – 50 GHz (Q-Band)
Installation of remaining four bands completed late-2012.
2 GHz-wide bandwidth available now on all bands.
8 GHz-wide bandwidth available end of 2012.
Correlator installation (nearly) complete.
– Basic (‘continuum’ and spectral survey) modes working well.
– Flexible tuning modes nearly ready.
– Some special modes (phased array, subarrays) available soon.
Full-Band Receiver
Availability Timescale
• Four receiver bands are now fully outfitted: C band (4 – 8 GHz), and K,
Ka, Q: (18 – 50 GHz).
• At 1—2 and 8—12
GHz, all antennas
are equipped with a
mix of old/new
receivers
• 2 – 4 and 12 – 18
GHz band receivers
are new.
• Full-bandwidth
availability (8
GHz/pol.) awaiting
high-speed sampler
installation.
Getting On the EVLA
• There are two programs for getting on the EVLA:
– OSRO (Open Shared Risk Observing)
– RSRO (Resident Shared Risk Observing).
• OSRO:
– No residency requirement – you can stay home.
– Visibility data available from archive via ftp, or by disk
shipment.
– Maximum bandwidth: 2 GHz (starting Sept 2011)
• Configured as two separate tunings, each up to 1 GHz wide.
• Eight contiguous subbands within each tuning.
– Standard observing mode provides full polarization, with
64 channels per visibility product.
OSRO Spectral Resolutions
• There are 13 different subband (spectral window) widths
available to OSRO:
Total Bandwidth
Subband Width
Channel Res.
MHz
MHz
kHz
2048
128
2000
1024
64
1000
…
…
…
.03125
.488
0.15
• All subbands must be adjacent, with same width and channel
resolution.
• Time resolution: 1 second minimum (default for A-Cfg.)
• Doppler setting available for each scan.
• Access via existing time allocation process.
RSRO Capabilities
•
•
•
•
RSRO gives users access to more advanced modes.
Requires extended residency in Socorro
Up to 25% of all observing time available for this pgm.
Major advantage: More spectral resolution:
Subband Width
Nchan/Product
Channel Res.
MHz
kHz
128
64
2000
64
128
500
…
…
…
0.5
16384
.031
…
…
…
.03125
16384
.0019
• Next step: flexible tuning of subbands…
Expanding RSRO Capabilities
• As commissioning and development proceeds, more
complex correlator modes become available, including
– Recirculation: doubles spectral resolution for each halving of the
subband width (assumed in previous table).
– Individual subband tuning: Allows specific targeting of individual
spectral transitions.
– Individual subband tuning with individual subband widths.
– Access to full bandwidth observing: Full 8 GHz bandwidth comes
on line in 2012.
• Difficult to predict when these enhanced capabilities will
be available, but all are under active development now.
• RSRO participants expected to assist in EVLA
commissioning and development.
Two Routes to RSRO
• A: An Accepted Scientific Proposal
– At least one ‘expert’ per proposal to assist with commissioning
• ‘Black Belt’ status not required
• Enthusiasm and willingness to learn is required!
– Apply via regular proposal process
•
•
•
•
Two extra pages justification permitted
Science justification required
Technical section (‘How we can help’)
Budget section (if NRAO support is requested).
– One month residency required for each 20 hours of EVLA time.
• Minimum of 3 months.
• Single visit preferred.
• B: Apply to the NM Assistant Director for residency
– Justify your technical capabilities and costs.
– ‘Time served’ will be credited for future proposals.
Submitting Your EVLA Proposal
• Use NRAO’s Proposal Submission Tool
• Normal proposals
–
–
–
–
–
–
Semester system
Submission deadlines are August 1 and February 1
Types are Regular, Large and Triggered
2011 August 1 deadline: configurations C, CnB and B
2012 February 1 deadline: configurations BnA and A
At any deadline, requests for future configurations will also be
considered
• Director’s Discretionary Time proposals
– May be submitted 24/7
– Types are Exploratory and Target of Opportunity
EVLA Data Products
•
•
•
•
Data are in form of visibilities.
No ‘reference images’ available yet.
Data volumes can be large (up to 1 TB).
OSRO data can be collected through the archive (smaller
volumes) or sent on external disk.
• RSRO data available from archive in Socorro.
• OSRO data can be reduced in AIPS or CASA
• RSRO data are expected to be reduced in CASA
– Many RSRO setups can be calibrated via AIPS.
• Remember: The ‘SR’ in OSRO and RSRO stands for
‘Shared Risk’ – no guarantees!
On-Line Help
• Virtually all the information (and much much more!) given
in this presentation is available online
• Start at:
https://science.nrao.edu/facilities/evla
Wide-band Galactic Plane Survey: Pilot Project
G55.7+3.4
1.2-1.9GHz
Res: 30”
RMS: 10 uJy/b
Spectral Index
UC HII Region
Flat Spectrum
2deg
Non-thermal
synchrotron
Wide-field, wide-band,
high dynamic range
imaging: simultaneous
total intensity and
spectral index