The Future of the GBT

Felix J. Lockman NRAO Green Bank

Arecibo, July 2009 UNOFFICIAL The Future of the GBT

Felix J. Lockman NRAO Green Bank

Arecibo, July 2009 Characteristics of the GBT

Large Collecting Area Sensitive to Low Surface Brightness Sky Coverage & Tracking (>85%) Angular Resolution Frequency Coverage Radio Quiet Zone Unblocked Aperture

state-of-art receivers & detectors modern control software ﬂexible scheduling

Unique capabilities which complement EVLA, VLBA, and ALMA

The Advantage of Unblocked Optics Dynamic Range Near sidelobes reduced by a factor >10 from conventional antennas Gain & Sensitivity The 100 meter diameter GBT performs better than a 120 meter conventional antenna Reduced Interference

2002 panels active surface retroreﬂectors for future metrology

A telescope designed to be enhanced Unique active surface →Unlike any other radio telescope← Green Bank and the GBT A telescope that works well over a factor of 1000 in frequency/wavelength / energy -- equivalent to the range from the infrared (10μ) to the soft X-ray (0.01μ)

GALEX HST

Chandra Spitzer “...just hitting its stride”

Future Prospects & Development at NRAO and in the US Radio Community ~ 2008 NRAO Staff Retreat 4 AOC Auditorium, NRAO, Socorro, NM ~ April 10-11, 2008 A telescope for fundamental physics

The fastest pulsars test our understanding of matter at the most extreme densities “A Radio Pulsar Spinning at 716 Hz” Hessels et al 2006 Science A telescope for fundamental physics

The fastest pulsars test our understanding Timing of pulsars gives the most stringent of matter at the most extreme densities tests of theories of gravity

“Tests of General Relativity from Timing the Double Pulsar” Kramer et al 2006 Science

Large Collecting Area Sensitive to Low Surface Brightness Sky Coverage & Tracking (>85%) Angular Resolution Frequency Coverage Radio Quiet Zone Unblocked Aperture A telescope for understanding star formation

Molecules as astrophysical probes: NH3, CCS, HCN, CO...

The internal structure of An Infrared Dark Cloud star-forming clouds: temperature, density, turbulence, chemical composition “The Nature of the Dense Core Population in the Pipe Nebula: A Survey of NH3, CCS and HC5N Molecular Line Emission” Rathborne et al 2008 ApJS

GBT beam in NH3 at 24 GHz

GBT beam in CO at 115 GHz

We need multi-pixel focal plane cameras (arrays) A telescope for understanding star formation

Molecules as astrophysical probes: NH3, CCS, HCN, CO...

GBT beam in NH3 at 24 GHz

Large Collecting Area GBT beam in CO at 115 GHz Sensitive to Low Surface Brightness Sky Coverage & Tracking (>85%) Angular Resolution Frequency Coverage We need multi-pixel Radio Quiet Zone focal plane cameras (arrays) Unblocked Aperture A telescope for understanding the origin of galaxies

Detection of highly-redshifted lines of CO, HI, OH, ...

Riechers et al 2006 CO(1-0) at z=4.7

York et al 2007 (432 MHz) Kanekar et al 2006 (424 MHz) DLya HI at z=2.3 HI at z=2.35

HI and FeII DLya z=2.3 A telescope for understanding the origin of galaxies

Detection of highly-redshifted lines of CO, HI, OH, ...

Riechers et al 2006 CO(1-0) at z=4.7 The only telescope which will be able to observe CO(1-0) at essentially all redshifts York et al 2007 (432 MHz) Kanekar et al 2006 (424 MHz) DLya HI at z=2.3 HI at z=2.35

Large Collecting Area Sensitive to Low Surface Brightness Sky Coverage & Tracking (>85%) Angular Resolution HI and FeII Frequency Coverage DLya z=2.3 Radio Quiet Zone Unblocked Aperture A telescope for solar system studies

Goldstone + GBT Bistatic Radar

“Large Longitude Libration of Mercury Reveals a Molten Core” Margot et al. 2007 Science A telescope for solar system studies

Arecibo + GBT Bistatic Radar angular resolution to 20 meters (11 mas) circular polarization at 100m resolution (left)

“No Evidence for Thick Deposits of Ice at the Lunar south Pole” Campbell et al 2006 Nature

Large Collecting Area Sensitive to Low Surface Brightness Sky Coverage & Tracking (>85%) Angular Resolution Frequency Coverage Radio Quiet Zone Unblocked Aperture A Number of “Large” Projects Underway

The Pulsar Timing Array Search for Gravitational Radiation Demorest et al (510 h)

Search for Planets Around M Dwarfs (VLBA + VLA) Bower et al (1400 h)

Magnetic Fields in Star Forming Clouds Crutcher et al (300h)

H2O Megamaser Survey to determine H0 (with VLBA) Braatz et al (580 h)

Chemical Inventory of Sgr B2 (0.3 - 50 GHz) Hollis et al (624 h) Using Pulsars to detect nHz gravity waves

Large Collecting Area Sensitive to Low Surface Brightness Sky Coverage & Tracking (>85%) Angular Resolution Frequency Coverage Radio Quiet Zone Unblocked Aperture A telescope for cosmology

Discovered by the GBT Monitored by the GBT Imaged by VLBA (+GBT) Large Collecting Area Sensitive to Low Surface Brightness Sky Coverage & Tracking (>85%) Angular Resolution Frequency Coverage Radio Quiet Zone Unblocked Aperture

Mass of the black hole Conditions in accretion disks

Determination of H0 A telescope for Interstellar organic chemistry

12 new organic molecules detected with the GBT including the ﬁrst interstellar anions: - - C6H & C8H

“Possible Gas-phase Syntheses for Seven Neutral Molecules Studied Recently with the Green Bank Telescope” Quan & Herbst 2007, A&A

Connecting the chemistry of interstellar space with the chemistry of the solar system and the origin of life on earth. Large Collecting Area Sensitive to Low Surface Brightness Sky Coverage & Tracking (>85%) Angular Resolution Frequency Coverage Radio Quiet Zone Unblocked Aperture A telescope for understanding the evolution of galaxies

“On the continuing formation of the Andromeda Galaxy: Detection of HI Clouds in the M31 Halo” Westerbork + GBT Thilker et al 2004 ApJ A telescope for understanding the evolution of galaxies

“On the continuing formation of the Andromeda Galaxy: Detection of HI Clouds in the M31 Halo” Westerbork + GBT Thilker et al 2004 ApJ

“Neutral Hydrogen clouds in the M81/M82 Group” Chynoweth et al. 2008 AJ

Large Collecting Area Sensitive to Low Surface Brightness Sky Coverage & Tracking (>85%) Angular Resolution Frequency Coverage Radio Quiet Zone Unblocked Aperture Optical + GBT + VLA The ongoing evolution of the Milky Way

Hydrogen in the Milky Way

The Smith Cloud Smith’s Cloud as seen by the GBT in HI “The Smith Cloud: A High-Velocity Cloud Colliding with the Milky Way” Lockman et al. 2008 ApJL

Large Collecting Area Sensitive to Low Surface Brightness Sky Coverage & Tracking (>85%) Angular Resolution Frequency Coverage Radio Quiet Zone Unblocked Aperture Chemistry Cosmology Compact Objects Magnetic Fields The scientiﬁc grasp HI, OH z≥0 Star Formation of the GBT High-z molecules Nearby Galaxies Planet Search Solar System The GBT’s receivers

1-2 GHz 18-26 GHz 08A Proposals

42-50 GHz 5 GHz 0.8 GHz

0.3 GHz MUSTANG

Many shared resources among experiments Green Bank Telescope track replacement Summer 2007

Drift Survey for Pulsars Summer 2007 Data reduction by West Virginia High School Students www.as.wvu.edu/~pulsar

www.gb.nrao.edu/epo/psc.shtml

>100 TBy of pulsar search data A strong connection between astronomical research and regional education, supported by a $900k grant from NSF Education Directorate The Potential of the GBT The ﬁeld of view of the GBT at K band (for example) has We currently detect 1-2 >3000 Nyquist pixels with ηa > 55% Focal Plane Usage < 1/1500

21 The Potential of the GBT The ﬁeld of view of the GBT at K band (for example) has We currently detect 1-2 >3000 Nyquist pixels with ηa > 55% Focal Plane Usage < 1/1500

The frequency coverage of the We currently detect 3 GHz GBT is >100 GHz of instantaneous spectrum (much less at good resolution)

21 The Potential of the GBT The ﬁeld of view of the GBT at K band (for example) has We currently detect 1-2 >3000 Nyquist pixels with ηa > 55% Focal Plane Usage < 1/1500

The frequency coverage of the We currently detect 3 GHz GBT is >100 GHz of instantaneous spectrum (much less at good resolution)

Instantaneous Spectrum Usage < 3/100

Current GBT: Information detected / Available information ≲ 10-5

21 The FUTURE Better surface, pointing More use of ﬁeld-of-view More grasp of spectrum More detectors

3mm Wide-ﬁeld Bolometer Arrays Spectroscopic Focal Plane arrays Phased-array receivers Detector Development RFI Cancellation Bandwidth

Now for something completely different... The FUTURE Better surface, pointing More use of ﬁeld-of-view More grasp of spectrum More detectors

3mm Wide-ﬁeld Bolometer Arrays Spectroscopic Focal Plane arrays Phased-array receivers Detector Development RFI Cancellation Bandwidth

Now for something completely different... MUSTANG, a 64 pixel 3mm bolometer array

First Light at 3mm (9” HPBW)

MASTERCAM, a 1000 pixel 3mm bolometer array Tsys=27 K

A 7-pixelA spectroscopic spectroscopic focal focalplane plane array array forfor the the 18-26 18-26 GHz GHz band band A 7-pixelA spectroscopic spectroscopic focal focalplane plane array array forfor the the 18-26 18-26 GHz GHz band band The push to 3mm spectroscopy

A 100-pixel 70-115 GHz spectroscopic array IC 342 HI, CO, GBT 3mm-array Footprint November 15, 1988 November 16, 1988 November 16, 1988

7-feed 5 GHz FPA

Overcoming Limits

Surface

Optics Efficiency and Gain

33 Overall 300μ

Inner 60 m 210μ

The Green Bank Science Education Institute A resource for science education

39 The center for science education will serve

Professionals Faculty at teaching Colleges K-12 faculty Astronomy students Regional K-12 students General public Site visitors

A regional and national resource

A new kind of institution bridging the research and educational communities

A new, separate division of NRAO, tightly coupled to GB operations The Green Bank Telescope Array

Big dish with FPAs + Many small dishes

A spectroscopic focal plane array for the 18-26 GHz band