NewsletterNumber 31 July 2001

GONG+ is Online!Last October, GONG celebrated its fth birthday, and turning ve brought with it celebration and reec-tions on past accomplishments, but it also presented an opportunity to look ahead to new goals and new directions for the future – foremost, completing the camera upgrade that we are calling GONG+, and

next on the horizon, implementing GONG++, the high-performance computing capability needed to process the high resolution GONG data. Readying the new camera systems for deployment has kept everyone extremely busy. We have continued to oper-ate and maintain the GONG Classic network, support the GONG+ deployment effort, and prepare for the transition to GONG+ network operations and data processing.

The path to deployment has been challenging, but all of the milestones were eventually passed. The

Deployment Readiness Review, at the end of Feb-ruary, with GONG alumni Jim Kennedy, Rob Hub-bard, Lonnie Cole, and Bret Goodrich, along with SOLIS’s Jeremy Wagner, helped us review the sit-uation and commit to the transition to GONG+ and bringing down GONG Classic. Since then it’s

been an exciting time for the GONG team around the world. We completed deployments at Big Bear (March 23), CTIO (April 20), and Learmonth (May 11), and at that time, with three sites in operation, we ofcially transitioned to GONG+. The deploy-ment nished up with installations at Udaipur (June 21), Mauna Loa (June 22), and El Teide (July 27). The deployments have incorporated the transplant of the GONG+ camera system and preventative mainte-nance work, which has been delayed to coincide with the deployments and is long overdue.

The rst Big Bear GONG+ data for 7 hours showing excellent sensitivity out to l ≈ 1000.

Hats off to our deployment teams – they have done a lot of traveling in the last ve months and have done a great job.

The Project has had some comings and goings in the GONG team here in Tucson. Susan Davidson, who was with GONG for over six years, and NOAO for nearly 25 years, retired at the begin-ning of February. She will be missed throughout the GONG community, and we wish her the very best in the future. Roberta Toussaint, who has been with GONG for nearly a decade, has moved over to NSO’s SOLIS Project. We look forward to her continued association with GONG, which has included her participation in the GONG+ deploy-ment. We also saw Tatia Wing move on and wish her the best in her new adventures. David Landy will be leaving at the end of the summer and setting new goals as a graduate student at Indiana University.

On the positive side of the ledger, Caroline Barban joined the Analysis Group and is working on improv-ing the mode parameter estimates by simultaneously tting the spectrum obtained in velocity and inten-sity. Guillermo Montijo was welcomed back into the fold. As many of you remember, he was a key player

in the production and deploy-ment of GONG Classic, and it is great to have him back on the team. Katrina Gressett, Simon Kras and Kerri Donald-son Hanna joined the DMAC group, and Jeffrey Sudol will be working with the Instrument Team.

Kiran Jain, from the Udaipur Solar Observatory, visited Tucson in February and March of this year, and was one of the rst GONG+ users, producing ring diagrams in both velocity and intensity.

GONG+ Instrument Team members (from left to right): Jean Goodrich, Roberta Toussaint, Roy Tucker,

Sang Nguyen, Guillermo Montijo, Lana Britanik, Bert Villegas, Ron Kroll, and Jack Harvey

A cut through 3-dimensional power spectra at 3.5 mHz for the velocity (left panel) and intensity (right panel). The spectra were generated by tracking a 20° by 20° region for 2 days as it crossed disk center. Each gure extends ± 2.2 Mm-1 k

x and k

y.

GONG-SOHO 2002Big Bear Solar Observatory - October 2002

Final dates and meeting information to follow via email, snail mail, and theGONG www server.

The GONG bibliography is being integrated into the Astrophysics Data System at http://adsabs.harvard.edu/Groups/search/Helioseismology or on the main ADS search form. Keep your pre/reprints coming.

What Data Can I Get from GONG?GONG provides data freely to its members. Becoming a member is simple — go to the GONG web page and select the “Scientic Enterprise” link and then the “GONG Membership Application” link and then the “GONG Research Program Application” link. You can ll out the forms electronically, or by using a text le. After the forms are submitted and processed, you will be able to search and order our data.

Some of the currently available products for the helioseis-mologist are:

Power spectra of solar oscillations covering the range of 0 ≤ l ≤ 200, -l ≤ m ≤ +l, and 0 ≤ ν ≤ 8.33 mHz.

Time series of complex spherical harmonic coefcients as a function of l and m in the range 0 ≤ l ≤ 200 and 0 ≤ |m| ≤ l.

Estimated frequencies, amplitudes, and linewidths of solar oscillation modes, as a function of l, m, and ν covering the range 0 ≤ l ≤ 150, -l ≤ m ≤ +l, and 1.2 ≤ ν ≤ 4.0 mHz.

Both the time series and power spectra are available for tem-poral intervals of GONG months (GM), with 1 GM ≡ 36 days. Note, however, that the mode parameters are com-puted from overlapping three-GM (108 day) temporal

intervals, with a one-GM spacing. Time series and power spectra are also available for 0 ≤ l ≤ 45 for intervals of 1 GONG Year (10 GM or 360 days) and 35 GM. All data from 7 May 1995 to 6 October 2000 have been processed to time series and power spectra, and the mode parameters have been computed on all possible 53 intervals of 3 GM. For the non-helioseismologist, we have:

• Minute-by-minute images of the solar surface Dop-pler velocity eld from 7 May 1995 to the present.

• Magnetograms every 20 minutes, plus derived synop-tic maps for Carrington rotation cycles 1896 through 1942; and

• Low-pass, temporally ltered, and geometrically reg-istered images of the surface Doppler velocity with a cadence of 4 minutes and a lter width of 17 minutes, useful for studies of slowly evolving ows from 7 May 1995 to 17 October 1998.

Finally, we have implemented a new data service that pro-vides near-real-time magnetograms with rough calibration and a cadence of about one every two hours around the clock. They can now be obtained at: ftp://www.gong.noao.edu/pub/gong/magnetograms

Sasha Kosovichev called attention to changes in GONG+ observations of the X20 are of April 2, 2001 in NOAA 9393, and Jack Harvey prepared this gure to show the temporal evolution. The left panel is the line-of-sight component of the magnetic eld near the northeast limb averaged over 30 minutes prior to the are (2100-2129 UT). The next six panels show the difference between the absolute value of the signal averaged over subsequent ten minute periods and the 30 minute pre-are average. White (black) represents increasing (decreasing) line-of-sight signal strength. The panels are averaged from left to right over 2130-39 (preare), 2140-49 (rising phase), 2150-59 (maximum), 2200-09 and 2210-2219 (declining phase), and 2250-59 (post are). The changes shown are a combination of seeing effects, change in perspective as the Sun rotates, line prole changes associated with the maximum phase of the are, normal evolution of the active region eld, and real eld changes associated with the are. The later panels are coincident with a strongly sheared sunspot. It is not clear if the are eld changes are in strength, direction or position or some combination.

Site Focus ... Mauna Loa Solar ObservatoryMauna Loa Solar Observatory (MLSO) is operated by the High Altitude Observatory (HAO), a division of the National Center for Atmospheric Research and funded by the National Science Foundation. The observatory is located at an elevation of 3,400 meters (11,000 feet) on the north slope of Mauna Loa which is an active shield volcano rising 4,200 meters (13,800 feet) above sea level on the Island of Hawaii. The Mauna Loa site was chosen for its unique properties that include a mountain thousands of kilo-meters away from any continental land mass, young lava, and lack of nearby vegetation. These factors keep local particulate contamination to a minimum and provide the clean, dry air and dark skies necessary for excep-tional coronal measurements. MLSO operates an assortment of instruments built by HAO and the NSO that observe the solar corona, chromosphere, pho-tosphere, and solar interior. HAO is dedicated to the study of the Sun and of the response of the Earth’s upper atmosphere to the Sun’s output. As a nationally sponsored laboratory, HAO is committed to the dissemination of its data to the community at large.

Data collected include: solar oscillations by GONG and ECHO, used to determine solar interior rotation rates and structure; photometry of the chromosphere and photosphere by PSPT (NSO) to study solar variability; chromospheric observations in Hα by PICS and Helium 1083 nm by CHIP; MK4 electron density images of the corona. PICS, CHIP and MK4 are used to study solar activity including coro-nal mass ejections and long-term solar cycle variability. Movies and images of present and past data are available via the internet at: http://mlso.hao.ucar.edu.

MLSO and GONG are guests on the National Oceanic and Atmospheric Administration’s (NOAA) Mauna Loa Observatory (MLO) site. (http://stratus.mlo.hawaii.gov.) MLO is a baseline station for NOAA’s Climate Monitoring and Diagnostics Laboratory (CMDL). CMDL conducts research related to atmospheric constituents such as gases, aerosols, solar radiation, meteorology, and precipitation chemistry that are capable of forcing change in the climate of the Earth’s environment. MLO also hosts cooperative programs with the Network for the Detection of Stratospheric Change and many other research institutions.

GONG’s web site http://www.gong.noao.edu is up-to-date with Project status, scientific investigations and publications, access to data products, and links to other activities within the field of helioseis-mology.

The FTP archives for GONG can be found at the anonymous FTP address: ftp://www.gong.noao.edu/pub/gong.

The GONG Newsletter is also available on GONG’s web site as a WWW document and an easily printable PDF document. We encour-age you to avail yourself of this service. You can be removed from the hardcopy mailing list, and added to the e-mail notification list, by simply sending an e-mail message to gong@noao.edu.

The GONG Project is funded by the National Science Foundation (NSF) through the National Solar Observatory (NSO), which is operated under a cooperative agreement between the Association of Universities for Research in Astronomy (AURA), Inc. and NSF.

The GLOBAL OSCILLATION NETWORK GROUPP.O. Box 26732Tucson, Arizona 85726-6732USA