Blar i forfatter "Solheim, Jan Erik"

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    • The Detection and Attribution of Northern Hemisphere Land Surface Warming (1850–2018) in Terms of Human and Natural Factors: Challenges of Inadequate Data 

      Soon, Willie; Connolly, Ronan; Connolly, Michael; Akasofu, Syun-Ichi; Baliunas, Sallie; Berglund, Johan; Bianchini, Antonio; Briggs, William M.; Butler, C.J.; Cionco, Rodolfo Gustavo; Crok, Marcel; Elias, Ana G.; Fedorov, Valery M.; Gervais, François; Harde, Hermann; Henry, Gregory W.; Hoyt, Douglas V.; Humlum, Ole; Legates, David R.; Lupo, Anthony R.; Maruyama, Shigenori; Moore, Patrick; Ogurtsov, Maxim; ÓhAiseadha, Coilín; Oliveira, Marcos J.; Park, Seok-Soon; Qiu, Shican; Quinn, Gerré; Scafetta, Nicola; Solheim, Jan Erik; Steele, Jim; Szarka, László; Tanaka, Hiroshi L.; Taylor, Mitchell K.; Vahrenholt, Fritz; Velasco Herrera, Víctor M.; Zhang, Weijia (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-28)
      A statistical analysis was applied to Northern Hemisphere land surface temperatures (1850–2018) to try to identify the main drivers of the observed warming since the mid-19th century. Two different temperature estimates were considered—a rural and urban blend (that matches almost exactly with most current estimates) and a rural-only estimate. The rural and urban blend indicates a long-term warming ...

    • The Everchanging Pulsating White Dwarf GD358 

      Solheim, Jan Erik; Kepler, S.O.; Nather, R. Edward; Gonzalez Perez, Jose M.; Johannessen, Frank; Winget, Don E.; Nitta, Atsuko; Kleinman, S. J.; Metcalfe, Travis; Sekiguchi, Kazuhiro; Xiaojun, Jiang; Sullivan, Denis; Sullivan, Tiri; Janulis, Rimvydas; Meistas, Edmund; Kalytis, Romualdas; Krzesinski, Jurek; Ogloza, Waldemar; O’Donoghue, Darragh; Romero-Colmenero, Encarni; Martinez, Peter; Dreizler, Stefan; Deetjen, Jochen; Nagel, Thorsten; Schuh, Sonja L.; Vauclair, Gerard; Ning, Fu Jian; Chevreton, Michel; Kanaan, Antonio; Costa, Jos´e Eduardo; Costa, Alex Fabiano Murillo; Wood, Matt A.; Silvestri, Nicole; Ahrens, T.J.; Jones, Aaron Kyle; Collins, Ansley E.; Boyer, Martha; Mukadam, Anjum; Klumpe, Eric W.; Larrison, Jesse; Kawaler, Steve; Riddle, Reed; Ulla, Ana; Bradley, Paul (Journal article; Tidsskriftartikkel; Peer reviewed, 2003-01-23)
      We report 323 hours of nearly uninterrupted time series photometric observations of the DBV star GD 358 acquired with the Whole Earth Telescope (WET) during May 23rd to June 8th, 2000. We acquired more than 232 000 independent measurements. We also report on 48 hours of time-series photometric observations in Aug 1996. We detected the non-radial g-modes consistent with degree ℓ = 1 and radial ...

    • HS 0705+6700: a new eclipsing sdB binary 

      Østensen, R.; Solheim, Jan Erik; Johannessen, F. (Journal article; Tidsskriftartikkel, 2001-10-09)
      We report the discovery of an eclipsing binary – HS 0705+6700 – being an sdB star with a faint companion. From its light curve the orbital period of 8263.87 s, the mass ratio of the system q = 0.28, the inclination of 84.◦4 and other system parameters are derived. The companion does not contribute to the optical light of the system except through a strong reflection effect. The semiamplitude of ...

    • The influence of solar system oscillation on the variability of the total solar irradiance 

      Yndestad, Harald; Solheim, Jan Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-08-30)
      Total solar irradiance (TSI) is the primary quantity of energy that is provided to the Earth. The properties of the TSI variability are critical for understanding the cause of the irradiation variability and its expected influence on climate variations. A deterministic property of TSI variability can provide information about future irradiation variability and expected long-term climate variation, ...

    • The long sunspot cycle 23 predicts a significant temperature decrease in cycle 24 

      Solheim, Jan Erik; Stordahl, Kjell; Humlum, Ole (Journal article; Tidsskriftartikkel; Peer reviewed, 2012-02-16)
      Relations between the length of a sunspot cycle and the average temperature in the same and the next cycle are calculated for a number of meteorological stations in Norway and in the North Atlantic region. No significant trend is found between the length of a cycle and the average temperature in the same cycle, but a significant negative trend is found between the length of a cycle and the ...

    • Multiwavelength observations revealing the outbursts of the two soft X-ray transients XTE J1859+226 and XTE J1118+480 

      Solheim, Jan Erik; Chaty, S.; Haswell, C.A.; Østensen, R.; Hynes, R.I.; Shrader, C.R.; Cui, W.; Mauche, C.W.; Norton, A.J.; Geballe, T.R.; Ioannou, Z.; King, A.R. (Conference object; Konferansebidrag, 2001-02-06)
      We report here on multiwavelength observations of the two new soft X-ray transients (SXTs) XTE J1859+226 and XTE J1118+480, which we observed with HST/RXTE/UKIRT. For XTE J1118+480 we also used EUVE since it is located at a very high galactic latitude and suffers from very low extinction. The two sources exhibited very different behaviour. XTE J1859+226 seems quite normal and therefore a good ...

    • The optical afterglow and host galaxy of GRB 000926 

      Fynbo, J.U.; Østensen, R.; Gorosabe, J.; Solheim, Jan Erik; Dall, T.H.; Hjorth, J.; Pedersen, H.; Andersen, M.I.; Møller, P.; Holland, S.; Smail, I.; Kobayashi, N.; Rol, E.; Vreeswijk, P.; Vrba, F.; Burud, I.; Jensen, B.L.; Henden, A.; Thomsen, B.; Canzian, B.; Castro Cer´on, J.M.; Castro-Tirado, A.J.; Cline, T.; Goto, M.; Greiner, J.; Hanski, M.T.; Hurley, K.; Pursimo, T.; Lund, N.; Tanvir, N.; Terada, H. (Journal article; Tidsskriftartikkel, 2001-04-11)
      We present the discovery of the Optical Transient (OT) of the long–duration gamma-ray burst GRB 000926. The optical transient was detected independently with the Nordic Optical Telescope and at Calar Alto 22.2 hours after the burst. At this time the magnitude of the transient was R = 19.36. The transient faded with a decay slope of about 1.7 during the first two days after which the slope increased ...

    • The pulsation modes of the pre-white dwarf PG 1159-035 

      Costa, J. E. S.; Solheim, Jan Erik; Kepler, S. O.; Winget, D. E.; O’Brien, M. S.; Kawaler, S. D.; Costa, A. F. M.; Giovannini, O.; Kanaan, A.; Mukadam, A. S.; Mullally, F.; Nitta, A.; Provenc, J. L.; Shipman, H.; Wood, M. A.; Ahrens, T. J.; Grauer, A.; Kilic, M.; Bradley, P. A.; Sekiguchi, K.; Crowe, R.; Jiang, X. J.; Sullivan, D.; Sullivan, T.; Rosen, R.; Clemens, J. C.; Janulis, R.; O’Donoghue, D.; Ogloza, W.; Baran, A.; Silvotti, R.; Marinoni, S.; Vauclair, G.; Dolez, N.; Chevreton, M.; Dreizler, S.; Schuh, S.; Deetjen, J.; Nagel, T.; Gonzalez Perez, J. M.; Ulla, A.; Barstow, Martin; Burleigh, M.; Good, S.; Metcalfe, T.S.; Kim, S.-L.; Lee, H.; Sergeev, A.; Akan, M.C.; Çakırlı, Ö.; Paparo, M.; Viraghalmy, G.; Ashoka, B. N.; Handler, G.; Hürkal, Özlem; Johannessen, F.; Kleinman, S. J.; Kalytis, R.; Krzesinski, J.; Klumpe, E.; Larrison, J.; Lawrence, T.; Meištas, E.; Martinez, P.; Nather, R. E.; Fu, J.-N.; Pakštienė, E.; Rosen, R.; Romero-Colmenero, E.; Riddle, R.; Seetha, S.; Silvestri, N. M.; Vučković, M.; Warner, B.; Zola, S.; Althaus, L. G.; Córsico, A. H.; Montgomery, M. H. (Journal article; Tidsskriftartikkel; Peer reviewed, 2008)
      Context. PG 1159-035, a pre-white dwarf with Teff ≃ 140 000 K, is the prototype of both two classes: the PG 1159 spectroscopic class and the DOV pulsating class. Previous studies of PG 1159-035 photometric data obtained with the Whole Earth Telescope (WET) showed a rich frequency spectrum allowing the identification of 122 pulsation modes. Analyzing the periods of pulsation, it is possible to ...

    • Understanding the Cool DA White Dwarf Pulsator, G29–38 

      Solheim, Jan Erik; Kleinman, S. J.; Bruvold, A.; Nather, R. E.; Winget, D. E.; Clemens, J. C.; Bradley, A.; Kanaan, A.; Claver, C. F.; Watson, T. K.; Yanagida, K.; Nitta, A.; Dixson, J. S.; Grauer, A. D.; Hine, B. P.; Fontaine, G.; Liebert, James; Sullivan, D. J.; Wickramasinghe, D. T.; Achilleos, N.; Mara, T. M. K.; Seetha, S.; Ashoka, B. N.; Leibowitz, E. M.; Moskalik, P.; Krzesi´nski, J.; O’Donoghue, D.; Kurtz, D. W.; Warner, B.; Martinez, Peter; Dolez, N.; Chevreton, M.; Barstow, M. A.; Kepler, S. O.; Giovannini, O.; Hansen, C. J.; Augusteijn, T. (Journal article; Tidsskriftartikkel; Peer reviewed, 1997-10-10)
      The white dwarfs are promising laboratories for the study of cosmochronology and stellar evolution. Through observations of the pulsating white dwarfs, we can measure their internal structures and compositions, critical to understanding post main sequence evolution, along with their cooling rates, allowing us to calibrate their ages directly. The most important set of white dwarf variables to ...

    • The WSO, a world-class observatory for the ultraviolet 

      Solheim, Jan Erik; Barstow, M.A.; Binette, L.; Brosch, N.; Cheng, F-Z.; Dennefeld, M.; Gomez de Castro, A.I.; Haubold, H.; van der Hucht, K.A.; Kappelmann, N.; Martinez, P.; Ribak, E.N.; Moisheev, A.; Pagano, I.; Sahade, J.; Wamsteker, W.; Werner, K.; Becker-Ross, H.; Florek, S.; Shustov, B. (Conference object; Konferansebidrag, 2002-09-17)
      The World Space Observatory is an unconventional space project proceeding via distributed studies. The present design, verified for feasibilty, consists of a 1.7-meter telescope operating at the second Largangian point of the Earth-Sun system. The focal plane instruments consist of three UV spectrometers covering the spectral band from Lyman alpha to the atmospheric cutoff with R~55,000 and offering ...

    • WSO/UV: World Space Observatory/Ultraviolet 

      Solheim, Jan Erik; Hernanza, M.; González-Riestra, R.; Wamsteker, W.; Shustov, B.; Barstow, M.; Brosch, N.; Fu-Zhen, C.; Dennefeld, M.; Dopita, M.; Gómez de Castro, A.I.; Kappelmannc, N.l.; Pagano, I.; Sahade, J.; Haubold, H.; Solheim, J.-E.; Martínezc, P. (Journal article; Tidsskriftartikkel, 2002-11-05)
      We summarize the capabilities of the World Space Observatory (UV) Project (WSO/UV). An example of the importance of this project (with a planned launch date of 2007/8) for the study of Novae is given.