Observing the Sun with the Atacama Large Millimeter/submillimeter Array (ALMA): Fast-Scan Single-Dish Mapping

Abstract

The Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope has commenced science observations of the Sun starting in late 2016. Since the Sun is much larger than the field of view of individual ALMA dishes, the ALMA interferometer is unable to measure the background level of solar emission when observing the solar disk. The absolute temperature scale is a critical measurement for much of ALMA solar science, including the understanding of energy transfer through the solar atmosphere, the properties of prominences, and the study of shock heating in the chromosphere. In order to provide an absolute temperature scale, ALMA solar observing will take advantage of the remarkable fast-scanning capabilities of the ALMA 12 m dishes to make single-dish maps of the full Sun. This article reports on the results of an extensive commissioning effort to optimize the mapping procedure, and it describes the nature of the resulting data. Amplitude calibration is discussed in detail: a path that uses the two loads in the ALMA calibration system as well as sky measurements is described and applied to commissioning data. Inspection of a large number of single-dish datasets shows significant variation in the resulting temperatures, and based on the temperature distributions, we derive quiet-Sun values at disk center of 7300 K at \(\lambda = 3~\mbox{mm}\) and 5900 K at \(\lambda = 1.3~\mbox{mm}\). These values have statistical uncertainties of about 100 K, but systematic uncertainties in the temperature scale that may be significantly larger. Example images are presented from two periods with very different levels of solar activity. At a resolution of about \(25''\), the 1.3 mm wavelength images show temperatures on the disk that vary over about a 2000 K range. Active regions and plages are among the hotter features, while a large sunspot umbra shows up as a depression, and filament channels are relatively cool. Prominences above the solar limb are a common feature of the single-dish images.

This is a preview of subscription content, access via your institution.

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13

Notes

  1. 1.

    Fast-scanning observing with the ALMA dishes was initially developed by Richard Hills and Neil Phillips, with non-solar observing in mind, during several commissioning campaigns starting in 2010. These efforts are documented in the ALMA Commissioning and Science Verification task CSV-203 and attached sub-tasks; specific solar developments are documented under CSV-3162 (2014 campaign) and CSV-3244 (2015).

  2. 2.

    The 25 12 m antennas built for ALMA by the AEM Consortium, normally used for interferometer observations, are also direct-drive antennas that perform well as fast-scanning dishes, but they are not discussed in this article.

  3. 3.

    The solar team can confirm that trying to observe at higher elevations does drive the antennas into a non-functioning state: the prolonged excessive accelerations can cause the drive power amplifiers of the PM antennas to trigger an overcurrent cut-out, requiring manual reset by a human at the antenna to recover operation.

  4. 4.

    Technically, this measurement is on the “\(T_{\mathrm{R}}^{*}\)” temperature scale (Jewell, 2002), but since the Sun is so much larger than the beam, the source-coupling factor can be assumed to be unity, and effectively this is the true source brightness temperature.

  5. 5.

    Note that in the standard CASA single-dish calibration script this correction is applied as a “gain” in the gencal task. Since gains refer to values for each antenna that are then multiplied together in pairs to correct visibilities between two antennas, in the case of single-dish data, the gain supplied is the inverse square-root of the correction factor. Alternatively, the correction factor can be applied directly after the imaging step with the immath task.

  6. 6.

    Solar single-dish data should be processed with CASA version 4.7 or later versions.

References

  1. Bastian, T.S., Ewell, M.W., Zirin, H.: 1993, The center-to-limb brightness variation of the sun at \(\mbox{lambda} = 850~\mbox{microns}\). Astrophys. J. 415, 364. DOI . ADS .

    ADS  Article  Google Scholar 

  2. Brajša, R., Benz, A.O., Temmer, M., Jurdana-Šepić, R., Šaina, B., Wöhl, H.: 2007, An interpretation of the coronal holes’ visibility in the millimeter wavelength range. Solar Phys. 245, 167. DOI . ADS .

    ADS  Article  Google Scholar 

  3. Brogan, C.L., Hunter, T.R.: 2014, ALMA Single-Dish Imaging Parameters. NAASC Memo 114 (draft).

  4. Broguière, D., Lucas, R., Pardo, J., Roche, J.-C.: 2011, TELCAL: The on-line calibration software for ALMA. In: Evans, I.N., Accomazzi, A., Mink, D.J., Rots, A.H. (eds.) Astronomical Data Analysis Software and Systems XX CS-442, Astron. Soc. Pacific, San Francisco, 277. ADS .

    Google Scholar 

  5. Buhl, D., Tlamicha, A.: 1970, The mapping of the Sun at 3.5 MM. Astron. Astrophys. 5, 102. ADS .

    ADS  Google Scholar 

  6. Carlsson, M., Hansteen, V.H., Gudiksen, B.V., Leenaarts, J., De Pontieu, B.: 2016, A publicly available simulation of an enhanced network region of the Sun. Astron. Astrophys. 585, A4. DOI . ADS .

    ADS  Article  Google Scholar 

  7. Casalta, J.M., Molins, A., Bassas, M., Canchado, M., Creus, E., Tomàs, A.: 2008, ALMA front end amplitude calibration device design and measured performances. In: Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation, Proc. IEEE 7018, 701838. DOI . ADS .

    Google Scholar 

  8. Chamberlin, R.A., Bally, J.: 1995, The observed relationship between the South pole 225-GHz atmospheric opacity and the water vapor column density. Int. J. Infrared Millim. Waves 16, 907. DOI . ADS .

    ADS  Article  Google Scholar 

  9. Clark, T.A., Naylor, D.A., Tompkins, G.J., Duncan, W.D.: 1992, Extension of the solar limb and sub-millimeter and millimeter wavelengths. Solar Phys. 140, 393. DOI . ADS .

    ADS  Article  Google Scholar 

  10. Coates, R.J.: 1958, Measurement of solar radiation and atmospheric attenuation at 4.3-millimeters wavelength. Proc. IRE 46, 122.

    Article  Google Scholar 

  11. Delgado, G., Otárola, A., Belitsky, V., Urbain, D.: 1999, The Determination of Precipitable Water Vapour at Llano de Chajnantor from Observations of the 183 GHz Water Line. ALMA Memo 271, Joint ALMA Observatory, Santiago.

  12. Ekers, R.D., Rots, A.H.: 1979, Short spacing synthesis from a primary beam scanned interferometer. In: van Schooneveld, C. (ed.) IAU Colloq. 49: Image Formation from Coherence Functions in Astronomy 61, Reidel, Dordrecht. DOI . ADS .

    Google Scholar 

  13. Hills, R.E.: 2016, PM Antenna Servo Characterization. ALMA CSV-3243 Report.

  14. Hills, R.E.: 2010, Correcting for the effects of the atmosphere. In: ALMA Newsletter 6, ESO, Garching, 2. ADS .

    Google Scholar 

  15. Iguchi, S., Morita, K.-I., Sugimoto, M., Vila Vilaró, B., Saito, M., Hasegawa, T., Kawabe, R., Tatematsu, K., Seiichi, S., Kiuchi, H., Okumura, S.K., Kosugi, G., Inatani, J., Takakuwa, S., Iono, D., Kamazaki, T., Ogasawara, R., Ishiguro, M.: 2009, The Atacama Compact Array (ACA). Publ. Astron. Soc. Japan 61, 1. DOI . ADS .

    ADS  Article  Google Scholar 

  16. Iwai, K.: 2016a, Fast Scan Pattern Simulation. ALMA CSV-3244 Solar Commissioning Report.

  17. Iwai, K.: 2016b, Nonlinearity of ALMA Antennas in Detuning Mode 1. ALMA CSV-3246 Solar Commissioning Report.

  18. Iwai, K., Shimojo, M.: 2015, Observation of the chromospheric sunspot at millimeter range with the Nobeyama 45 m telescope. Astrophys. J. 804, 48. DOI . ADS .

    ADS  Article  Google Scholar 

  19. Jewell, P.R.: 2002, Millimeter wave calibration techniques. In: Stanimirovic, S., Altschuler, D., Goldsmith, P., Salter, C. (eds.) Single-Dish Radio Astronomy: Techniques and Applications CS-278, Astron. Soc. Pacific, San Francisco, 313. ADS .

    Google Scholar 

  20. Kaufmann, P., Strauss, F.M., Schaal, R.E., Laporte, C.: 1982, The use of the large mm-wave antenna at Itapetinga in high-sensitivity solar research. Solar Phys. 78, 389. DOI . ADS .

    ADS  Article  Google Scholar 

  21. Koda, J., Scoville, N., Sawada, T., La Vigne, M.A., Vogel, S.N., Potts, A.E., Carpenter, J.M., Corder, S.A., Wright, M.C.H., White, S.M., Zauderer, B.A., Patience, J., Sargent, A.I., Bock, D.C.J., Hawkins, D., Hodges, M., Kemball, A., Lamb, J.W., Plambeck, R.L., Pound, M.W., Scott, S.L., Teuben, P., Woody, D.P.: 2009, Dynamically driven evolution of the interstellar medium in M51. Astrophys. J. Lett. 700, L132. DOI . ADS .

    ADS  Article  Google Scholar 

  22. Kosugi, T., Ishiguro, M., Shibasaki, K.: 1986, Polar-cap and coronal-hole-associated brightenings of the sun at millimeter wavelengths. Publ. Astron. Soc. Japan 38, 1. ADS .

    ADS  Google Scholar 

  23. Kundu, M.R.: 1970, Solar active regions at millimeter wavelengths. Solar Phys. 13, 348. DOI . ADS .

    ADS  Article  Google Scholar 

  24. Kutner, M.L., Ulich, B.L.: 1981, Recommendations for calibration of millimeter-wavelength spectral line data. Astrophys. J. 250, 341. DOI . ADS .

    ADS  Article  Google Scholar 

  25. Labrum, N.R.: 1978, Evidence on chromospheric structure from observations of solar brightness distribution at millimeter wavelengths. Proc. Astron. Soc. Aust. 3, 256. ADS .

    ADS  Article  Google Scholar 

  26. Lindsey, C., Hudson, H.S.: 1976, Solar limb brightening in submillimeter wavelengths. Astrophys. J. 203, 753. DOI . ADS .

    ADS  Article  Google Scholar 

  27. Linsky, J.L.: 1973a, A recalibration of the quiet sun millimeter spectrum based on the moon as an absolute radiometric standard. Solar Phys. 28, 409. DOI . ADS .

    ADS  Article  Google Scholar 

  28. Linsky, J.L.: 1973b, The Moon as a proposed radiometric standard for microwave and infrared observations of extended sources. Astrophys. J. Suppl. 25, 163. DOI . ADS .

    ADS  Article  Google Scholar 

  29. Loukitcheva, M., Solanki, S.K., White, S.M.: 2006, The dynamics of the solar chromosphere: comparison of model predictions with millimeter-interferometer observations. Astron. Astrophys. 456, 713. DOI . ADS .

    ADS  Article  Google Scholar 

  30. Loukitcheva, M., Solanki, S.K., White, S.M.: 2014, The chromosphere above sunspots at millimeter wavelengths. Astron. Astrophys. 561, A133. DOI . ADS .

    ADS  Article  Google Scholar 

  31. Loukitcheva, M., Solanki, S.K., Carlsson, M., White, S.M.: 2015, Millimeter radiation from a 3D model of the solar atmosphere. I. Diagnosing chromospheric thermal structure. Astron. Astrophys. 575, A15. DOI . ADS .

    ADS  Article  Google Scholar 

  32. Loukitcheva, M., White, S.M., Solanki, S.K., Fleishman, G.D., Carlsson, M.: 2017, Millimeter radiation from a 3D model of the solar atmosphere. II. Chromospheric magnetic field. Astron. Astrophys. 601, A43. DOI . ADS .

    ADS  Article  Google Scholar 

  33. Lucas, R.: 2012, Temperature Scale Calibration. Unpublished talk for ALMA staff.

  34. Mangum, J.: 2002, Load calibration at millimeter and submillimeter wavelengths. ALMA Memo 434, Joint ALMA Observatory, Santiago.

  35. Mangum, J.G.: 1993, Main-beam efficiency measurements of the Caltech Submillimeter Observatory. Publ. Astron. Soc. Pac. 105, 117. DOI . ADS .

    ADS  Article  Google Scholar 

  36. Mangum, J.G., Emerson, D.T., Greisen, E.W.: 2007, The On The Fly imaging technique. Astron. Astrophys. 474, 679. DOI . ADS .

    ADS  Article  Google Scholar 

  37. Newstead, R.A.: 1969, Solar limb brightening and enhancement measurements at 1.2 mm. Solar Phys. 6, 56. DOI . ADS .

    ADS  Article  Google Scholar 

  38. Nikolic, B., Bolton, R.C., Graves, S.F., Hills, R.E., Richer, J.S.: 2013, Phase correction for ALMA with 183 GHz water vapour radiometers. Astron. Astrophys. 552, A104. DOI . ADS .

    ADS  Article  Google Scholar 

  39. Noyes, R.W., Beckers, J.M., Low, F.J.: 1968, Observational studies of the solar intensity profile in the far infrared and millimeter regions. Solar Phys. 3, 36. DOI . ADS .

    ADS  Article  Google Scholar 

  40. Pardo, J.R., Cernicharo, J., Serabyn, E.: 2001, Atmospheric Transmission at Microwaves (ATM): An improved model for millimeter/submillimeter applications. IEEE Trans. Antennas Propag. 49, 1683. DOI . ADS .

    ADS  Article  Google Scholar 

  41. Phillips, N., Hills, R., Bastian, T., Hudson, H., Marson, R., Wedemeyer, S.: 2015, Fast single-dish scans of the Sun using ALMA. In: Iono, D., Tatematsu, K., Wootten, A., Testi, L. (eds.) Revolution in Astronomy with ALMA: The Third Year CS-499, Astron. Soc. Pacific, San Francisco, 347. ADS .

    Google Scholar 

  42. Righini, G., Simon, M.: 1976, Solar brightness distribution at 350 and 450 microns. Astrophys. J. 203, L95. DOI . ADS .

    ADS  Article  Google Scholar 

  43. Shimojo, M., Bastian, T.S., Hales, A., White, S.M., Iwai, K., Hills, R.E., Hirota, A., Phillips, N.M., Sawada, T., Yagoubov, P., Siringo, G., Asayama, S., Sugimoto, M., Brajša, R., Skokić, I., Bárta, M., Kim, S., de Gregorio, I., Corder, S.A., Hudson, H.S., Wedemeyer, S., Gary, D.E., De Pontieu, B., Loukitcheva, M., Fleishman, G.D., Chen, B., Kobelski, A., Yan, Y.: 2017, Observing the Sun with ALMA: High Resolution Interferometric Imaging. Solar Phys. 292. DOI .

  44. Sinton, W.M.: 1952, Detection of millimeter wave solar radiation. Phys. Rev. 86, 424. DOI . ADS .

    ADS  Article  Google Scholar 

  45. Sugimoto, M., Kosugi, G., Iguchi, S., Iwashita, H., Saito, M., Inatani, J., Takahashi, T., Tasaki, M., Nakanishi, K., McMullin, J.P., Puga, J.P., Hoff, B., Norambuena, J., Kamazaki, T., Vila-Vilar, B., Ikenoue, B., Morita, K.-I., Asayama, S., Yamada, M., Kiuchi, H.: 2009, Beam pattern measurements and observational evaluations of the ALMA/ACA 12-m antenna. Publ. Astron. Soc. Japan 61, 451. DOI . ADS .

    ADS  Article  Google Scholar 

  46. Tamura, Y., Sugimoto, M.: 2012, Preliminary Analysis of the Forward Efficiency. ALMA System Verification Report SYS #132, Joint ALMA Observatory, Santiago.

  47. Tolbert, C.W., Straiton, A.W.: 1961, Solar emission at millimeter wavelengths. Astrophys. J. 134, 91. DOI . ADS .

    ADS  Article  Google Scholar 

  48. Ulich, B.L., Haas, R.W.: 1976, Absolute calibration of millimeter-wavelength spectral lines. Astrophys. J. Suppl. 30, 247. DOI . ADS .

    ADS  Article  Google Scholar 

  49. Urpo, S., Krüger, A., Hildebrandt, J.: 1986, Millimetre wave sources in the solar corona. Astron. Astrophys. 163, 340. ADS .

    ADS  Google Scholar 

  50. van Kempen, T., Corder, S., Lucas, R., Mauersberger, R.: 2012, How ALMA is calibrated. In: ALMA Newsletter 9, ESO, Garching, 8. ADS .

    Google Scholar 

  51. Vernazza, J.E., Avrett, E.H., Loeser, R.: 1976, Structure of the solar chromosphere. II. The underlying photosphere and temperature-minimum region. Astrophys. J. Suppl. 30, 1. DOI . ADS .

    ADS  Article  Google Scholar 

  52. Vršnak, B., Pohjolainen, S., Urpo, S., Terasranta, H., Brajša, R., Ruždjak, V., Mouradian, Z., Jurac, S.: 1992, Large-scale patterns on the sun observed in the millimetric wavelength range. Solar Phys. 137, 67. DOI . ADS .

    ADS  Article  Google Scholar 

  53. Warmels, R., Remijan, A.J.: 2017, ALMA Cycle 5 Technical Handbook, Joint ALMA Observatory, Santiago.

  54. Wedemeyer, S., Bastian, T., Brajša, R., Hudson, H., Fleishman, G., Loukitcheva, M., Fleck, B., Kontar, E.P., De Pontieu, B., Yagoubov, P., Tiwari, S.K., Soler, R., Black, J.H., Antolin, P., Scullion, E., Gunár, S., Labrosse, N., Ludwig, H.-G., Benz, A.O., White, S.M., Hauschildt, P., Doyle, J.G., Nakariakov, V.M., Ayres, T., Heinzel, P., Karlicky, M., Van Doorsselaere, T., Gary, D., Alissandrakis, C.E., Nindos, A., Solanki, S.K., Rouppe van der Voort, L., Shimojo, M., Kato, Y., Zaqarashvili, T., Perez, E., Selhorst, C.L., Barta, M.: 2016, Solar science with the Atacama Large Millimeter/submillimeter Array – A new view of our Sun. Space Sci. Rev. 200, 1. DOI . ADS .

    ADS  Article  Google Scholar 

  55. Wedemeyer-Böhm, S., Ludwig, H.G., Steffen, M., Leenaarts, J., Freytag, B.: 2007, Inter-network regions of the Sun at millimetre wavelengths. Astron. Astrophys. 471, 977. DOI . ADS .

    ADS  Article  Google Scholar 

  56. White, S.M.: 1999, Radio versus euv/x-ray observations of the solar atmosphere. Solar Phys. 190, 309. DOI . ADS .

    ADS  Article  Google Scholar 

  57. Whitehurst, R.N., Copeland, J., Mitchell, F.H.: 1957, Solar radiation and atmospheric attenuation at 6-millimeter wavelength. J. Appl. Phys. 28, 295. DOI . ADS .

    ADS  Article  Google Scholar 

  58. Wootten, A., Thompson, A.R.: 2009, The Atacama Large Millimeter/submillimeter Array. IEEE Proc. 97, 1463. DOI . ADS .

    ADS  Article  Google Scholar 

  59. Yagoubov, P.A.: 2013, Solar observations with ALMA – How to minimize saturation in SIS mixers. In: 38th International Conference on Infrared, Millimeter, and Terahertz Waves, IEEE, New York, 1. DOI . ADS .

    Google Scholar 

  60. Yagoubov, P.A., Murk, A., Wylde, R., Bell, G., Tan, G.H.: 2011, Calibration loads for ALMA. In: 36th International Conference on Infrared, Millimeter, and Terahertz Waves, IEEE, New York, 1. DOI .

    Google Scholar 

Download references

Acknowledgments

The ALMA solar commissioning effort was supported by ALMA Development grants from NRAO (for the North American contribution), ESO (for the European contribution), and NAOJ (for the East Asia contribution). The help and cooperation of the ALMA Extension and Optimization of Capabilities (EOC) team as well as the engineers, telescope operators, astronomers-on-duty, and staff at the ALMA Operations Support Facility was crucial for the success of solar commissioning campaigns in 2014 and 2015. We are grateful to the ALMA project for making solar observing with ALMA possible. R. Brajša acknowledges partial support of this work by the Croatian Science Foundation under the project 6212 “Solar and Stellar Variability” and by the European Commission FP7 project SOLARNET (312495, 2013 – 2017), which is an Integrated Infrastructure Initiative (I3) supported by the FP7 Capacities Programme. G. Fleishmann acknowledges support from NSF grants AGS-1250374 and AGS-1262772. Travel by Y. Yan to ALMA for the 2015 commissioning campaign was partially supported by NSFC grant 11433006.

Author information

Affiliations

Authors

Corresponding author

Correspondence to S. M. White.

Ethics declarations

Disclosure of Potential Conflicts of Interest

The authors declare that they have no conflicts of interest affecting this article.

Additional information

This article is a companion of the article available at doi: 10.1007/s11207-017-1095-2 .

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

White, S.M., Iwai, K., Phillips, N.M. et al. Observing the Sun with the Atacama Large Millimeter/submillimeter Array (ALMA): Fast-Scan Single-Dish Mapping. Sol Phys 292, 88 (2017). https://doi.org/10.1007/s11207-017-1123-2

Download citation

Keywords

  • Radio emission
  • Chromosphere
  • Heating, chromospheric
  • Instrumentation and data management