Max Planck Institute for Astronomy - Annual Report 2007

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38 II. Highlights the planet disappears behind the star (secondary cover) can be seen in the phase at around 0.5. Here the drop of the continuum is only 3.1 per thousand. Both independently obtained planetary spectra are shown in Fig. II.4.4. The measurement values (green triangles for the relative spectrum, blue dots for the absolute spectrum) correspond very well, thus strengthening the reliability of the calibration processes. As a result, the astronomers were able to obtain for the first time an exoplanet’s absolute spectrum. Given the precision of 0.1 % for the flow calibration, in the future this method should even permit the measurement of thermal emissions of the night side of the planet. As Fig. II.4.5 shows, it covers a flux range of 0.2 to 0.6 milli-Jansky. What conclusions about the atmosphere can be derived from this spectrum? A comparison of model spectra (Fig. II.4.6) allows for several statements that are made with caveats. The continuum matches a 1100 K hot atmosphere. A significant deviation in the continuum between 7.5 and 8.5 µm can be explained by the fact that the atmosphere transports a substantial amount of heat from the day to the night side. Furthermore a small structure appears at 8.1 µm with a statistical significance of 4 s. Nonetheless a decision cannot clearly be made as to whether this is due to an emission or an absorption feature. Also at 7.7 µm wavelength, an emission or an absorption line could be present. It was surprising that – in contrast to the “hot Jupiter” HD 189733b – no indications of water were found in the spectrum. The cause for this is still unclear. The strongest emission bands are expected by the researchers to appear in the near infrared where sp i t z e r can help to prove their existence. In the surroundings where H 2 O lines are likely, carbon monoxide (CO) and carbon dioxide (CO 2 ) would also be detectable. Transmission spectra could also aid in answering the question of the missing water. Somewhat simultaneous with the work of Swain, Bouwman, and colleagues, a publication came out by Jeremy Richardson’s group at Na s a’s Goddard Space Flight Center, who were also using sp i t z e r to observe HD 2095458. This group too found the wide modulation between 7.5 and 8.5 µm. However, they claimed to have additionally found a wide emission line around 9.65 µm which they traced back to silicates. This could not be confirmed by the Swain and Bouwman team. With this first measurement of an exoplanet’s absolutely calibrated spectrum, the astronomers now made an important step forward. The success increased confidence in the method with the consequence that the astronomers now plan to measure additional emission spectra of other transit planets and then of each planet’s full orbit. This way, one will be able to obtain the chemical composition of the planetary atmospheres under varying phase angles, from which conclusions about the chemical processes on the day and night sides can be derived. Processes such as photochemistry and heat distribution would then become accessible for the first time. The group has therefore submitted observation proposals for the sp i t z e r and Hu b b l e space telescopes. Observations with telescopes on earth, such as the InfraRed Telescope Facility (IRTF) on Mauna Kea, are also planned. Jeroen Bouwman In cooperation with: Jet Propulsion Laboratory, Pasadena, California Institute of Technology, Pasadena
II.5 Dwarf Galaxies Under the Magnifying Glass The first scientific work on the Large Binocular Telescope With the decisive participation of the MPIA, the Large Binocular Telescope (LBT) is coming to life on Mount Graham in Arizona. It is unique because two large primary mirrors on a common mounting gather the light of the stars and galaxies and direct it into a single focal point. In the spring of 2007, the scientific demonstration phase began with one of the two mirrors and a camera located at its primary focus. The first results of this new phase were published by an international astronomer team led by MPIA’s Matthew Coleman. The team studied three only recently discovered dwarf galaxies which are companions to our Milky Way System. The shape of the Hercules dwarf galaxy proved surprising: It is rather strongly flattened and is similar to a disk or a cigar. The reason for this has not been definitively clarified – it is Fig. II.5.1: The LBT with the two main mirrors. The first observations were made with the mirror on the right. (Picture: LBTO) possible that the Milky Way System’s gravitational field is deforming the dwarf galaxy. Both of the other dwarf galaxies, Canes Venatici I and Leo T are also rather interesting: Their stellar populations are of varying age, thus hinting at complex formation histories. Throughout 2007, the second mirror was also installed in the LBT (Fig. II.5.1) but the first observations were made with only the first of the two 8.4 meter mirrors. Here the Large Binocular Camera was made available with a primary focus on the blue channel (LBC Blue). LBC Blue and its future twin for the red spectral range, LBC Red, were developed by the Italian LBT partners. LBT Blue is equipped with four CCDs each having 2048 3 4608 pixel and creating a 23 by 23 square arc minutes field of view, corresponding almost to the size of the full moon. This camera is, to some extent, a 38 megapixel CCD wide-angle camera. It specializes in the wavelength region of 320 to 500 nm and is equipped with a range of standard color filters. 39
Page 1 and 2: Max Planck Institute for Astronomy
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Page 5: Contents Preface ..................
Page 8 and 9: 6 I. General I. General I.1 Scienti
Page 10 and 11: 8 I. General Planet and Star Format
Page 12 and 13: 10 I. General plementary. Ground-ba
Page 14 and 15: 12 I. General High-fidelity imagers
Page 16 and 17: 14 I. General Fig. I.6: Foreseen de
Page 18 and 19: 16 I. General I.3 National and Inte
Page 20 and 21: 18 I. General Edinburgh, University
Page 22 and 23: 20 II. Highlights II.1 Youngest Ext
Page 24 and 25: 22 II. Highlights radial velocity [
Page 26 and 27: 24 II. Highlights II.2 A Search for
Page 28 and 29: 26 II. Highlights F 1 [5] -2 0 2 4
Page 30 and 31: 28 II. Highlights Number of Planets
Page 32 and 33: 30 II. Highlights z [AU] z [AU] 1 0
Page 34 and 35: 32 II. Highlights t =0 T orb t =1 T
Page 36 and 37: 34 II. Highlights II.4 An Exoplanet
Page 38 and 39: 36 II. Highlights F / F 12m 4 3 2
Page 42 and 43: 40 II. Highlights The Hercules Dwar
Page 44 and 45: 42 II. Highlights on the giant bran
Page 46 and 47: 44 II. Highlights II.6 Black Hole A
Page 48 and 49: 46 II. Highlights F [10 -23 W cm -
Page 50 and 51: 48 II. Highlights Flux [10 -23 W cm
Page 52 and 53: 50 II. Highlights Fig. II.7.2: A 22
Page 54 and 55: 52 II. Highlights i [mag] i [mag] 1
Page 56 and 57: 54 II. Highlights Follow-up Observa
Page 58 and 59: 56 II. Highlights II.8 Unique Galay
Page 60 and 61: 58 II. Highlights NGC5055 (M63) NGC
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Page 66 and 67: 64 III. Selected Research Areas III
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88 III. Selected Research Areas III
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90 III. Selected Research Areas mas
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92 IV. Instrumental Developments an
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100 IV. Instrumental Developments a
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118 V. People and Events Dr. Gerner
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120 V. People and Events Fig. V.2.2
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122 V. People and Events operated v
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124 V. People and Events Ludwig-Bie
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126 V. People and Events To interpr
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128 V. People and Events Within the
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130 V. People and Events Fig. V.5.1
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132 V. People and Events V.6 »A cl
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134 V. People and Events on through
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136 Staff Directors: Henning, Rix (
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138 Staff / Calar Alto / Department
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140 Teaching Activities / Service i
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142 Further Activities / Compatibil
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144 Cooperation with Industrial Com
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146 Conferences StageS workshop, MP
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148 Conferences Ralf Launhardt: Wor
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150 Conferences Anna Pasquali: ASU
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152 Publications Apai, D., A. Bik,
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154 Publications Chen, X. P., R. La
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156 Publications of an unusual dwar
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158 Publications Moreau, J. A. Peac
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160 Publications Pontoppidan, K. M.
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162 Publications Garching-Bonn Deep
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164 Publications Zirm, A. W., A. va
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166 Publications Linz, H., R. Klein
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168 Publications Güdel, M.: The su
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A656 Eppelheim Patrick- Henry- Sied
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Max Planck Institute for Astronomy - Annual Report 2007

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