Giant Radio Jet Coming from Wrong Kind of Galaxy
Hubble Release Number: STScI-2003-04

A case for 7mm facilities at Mopra – VLBI
presented by P. Sparks at ATNF Thurs 21 April

Star Formation science

“Radio jets from black holes collapse gas clouds into stars” – van Bruegal et al, Jan 10 2005 (http://www.ucmerced.edu/news_articles/01102005_adjunct_professor_van_breugel.asp)

ASPECTS OF FEASIBILITY

They Were the First, and the Last, to Hear from Huygens
The Planetary Society, Feb 7 2005

Leonid Gurvits showed this slide at the January 15 press conference. The peak in the graph represents the successful calculation of interference fringes using the data from the Parkes and Mopra telescopes. When he showed the graph, Gurvits joked that it may look upside down, but this was natural because it was Australian data!

 

The Moment of Truth

As the morning progressed, the control room at Green Bank began to fill. In addition to Asmar and his colleagues, there were a few European workers there to conduct a Very Long Baseline Interferometry experiment (more on that below), and curious Green Bank staff members who could not stay away.

Green Bank Was Just the Beginning............

Meanwhile, 16 other radio telescopes around the world were trained on Huygens. Very Long Baseline Array antennas at Kitt Peak, Pie Town, Owens Valley, and Mauna Kea were quietly recording the data for later analysis, tracking Saturn across the night sky. Across the Pacific, radio astronomers in Japan and China waited for the Earth to turn and Saturn to rise in the east. In Australia, a team at Parkes stood by with a second Radio Science Receiver, getting ready to perform the real-time detection feat a second time.

Astronomers also recorded data at the Mopra telescope in Coonabarabran, New South Wales; in Ceduna, South Australia; and in Hobart, Tasmania.

On Jan. 14 at 10:18 UTC it was: 11:18 in Darmstadt, Germany 10:18 in London, England
05:18 in West Virginia
02:18 in Pasadena, California
21:18 in Sydney, Australia

   

Page created and maintained by Patricia Sparks. Comments and suggestions are most welcome. If you believe any important information has been omitted or have an idea for something you would like added to the site please direct your mail to psparks@phys.unsw.edu.au

VLBA OBSRVATIONS of 3C120 : NATURE |VOL 417 | 6 JUNE 2002 |

FROM NRAO site:
The VLBA is a system of ten radio-telescope antennas,each with a dish 25 meters (82 feet) in diameter and weighing 240 tons. From Mauna Kea on the Big Island of Hawaii to St. Croix in the U.S. Virgin Islands, the VLBA spans more than 5,000 miles, providing astronomers with the sharpest vision of any telescope on Earth or in space. Dedicated in 1993, the VLBA has an ability to see fine detail equivalent to being able to stand in New York and read a newspaper in Los Angeles.

"Giant jets of subatomic particles moving at nearly the speed of light have been found coming from thousands of galaxies across the Universe, but always from elliptical galaxies or galaxies in the process of merging — until now. Using the combined power of the Hubble Space Telescope, the Very Large Array (VLA) and the 8-meter Gemini-South Telescope, astronomers have discovered a huge jet coming from a spiral galaxy similar to our own Milky Way.
The discovery that the jet was coming from a spiral galaxy dubbed 0313-192 required using a combination of radio, optical and infrared observations to examine the galaxy and its surroudings."
Owen points out that 0313-192 resides in a cluster of galaxies called Abell 428. The scientists have discovered that Abell 428 is not a dense cluster, but rather a loose collection of small groups of galaxies.
In order to see the large jets so common to elliptical galaxies, Owen said, "you may need pressure from a cluster's intergalactic medium to keep the particles and magnetic fields from dispersing so rapidly that the jet can't stay together."
However, "A spiral won't survive in a dense cluster," Owen said. Thus, the looser collection of galaxy groups that makes up Abell 428 may be "just the right environment to allow the spiral to survive but still to provide the pressure needed to keep the jets together."
In any case, the unique example provided by this jet-producing spiral galaxy "raises questions about some of our basic assumptions regarding jet production in galaxies," Owen said.
From NRAO SITE
The Very Large Array, one of the world's premier astronomical radio observatories, consists of 27 radio antennas in a Y-shaped configuration on the Plains of San Agustin fifty miles west of Socorro, New Mexico. Each antenna is 25 meters (82 feet) in diameter. The data from the antennas is combined electronically to give the resolution of an antenna 36km (22 miles) across, with the sensitivity of a dish 130 meters (442 feet) in diameter.

VLBI notes (from http://lupus.gsfc.nasa.gov/brochure/bintro.html)

Over its 25-year history of development and operation the space geodetic technique called very long baseline interferometry (VLBI) has provided an unprecedented record of the motions of the solid Earth. VLBI is unique in its ability to define an inertial reference frame and to measure the Earth's orientation in this frame. Changes in the Earth's orientation in inertial space have two causes: the gravitational forces of the Sun and Moon and the redistribution of total angular momentum among the solid Earth, ocean, and atmosphere. VLBI makes a direct measurement of the Earth's orientation in space from which geoscientists then model such phenomena as atmospheric angular momentum, ocean tides and currents, and the elastic response of the solid Earth.
The Kokee Park Geophysical Observatory's 20-m VLBI antenna, on Kauai in the Hawaiian Islands, is operated by NASA's Space Geodesy Program in cooperation with the U.S. Naval Observatory.

Formation of the radio jet in M87 at 100 Schwarzschild radii from the central black hole
Nature 401, 891 - 892 (28 October 1999)

"Massive galaxies often are the source of well collimated jets of material that flow outwards for tens to hundreds of kiloparsecs from the regions surrounding the presumed black holes at their centres. The processes by which the jets are formed and collimated have been important problems for many years, and observations have hitherto had insufficient spatial resolution to investigate the length scales associated with these processes. Here we report observations at 43 GHz of the inner regions of the nearby active galaxy M87. The data show a remarkably broad jet having an 'opening angle' of 60° near the centre, with strong collimation of the jet occurring at 30–100 Schwarzschild radii (rS) from the black hole: collimation continues out to 1,000 rS. These results are consistent with the hypothesis that jets are formed by an accretion disk around the central black hole, which is threaded by a magnetic field."

"Centimetre-wavelength very-long-baseline interferometry (VLBI) has been used to study the M87 jet on parsec scales. At these resolutions the jet is quite narrow, and has an opening angle comparable to that measured on kiloparsec scales. To investigate the jet formation and to probe even finer scales, we have recently made VLBI observations with a global array of radio telescopes at a wavelength of 7 mm using the best available receivers and recording equipment. The principal target, M87 (3C274, J1230+1223), and a number of calibrator sources were observed with a global array of radio telescopes on 3 March 1999."