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Star Formation at High Redshifts and the Importance of Dust Obscuration

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Star Formation at High Redshifts and the Importance of Dust Obscuration Star Formation at High Redshifts and the Importance of Dust Obscuration Michał Jerzy Michałowski Supervisor: Jens Hjorth Co-supervisor: Darach Watson Thesis submitted for the degree of Philosophiæ Doctor Dark Cosmology Centre Niels Bohr Institut Det Naturvidenskabelige Fakultet Københavns Universitet Submitted October 15th, 2009 Defended December 4th, 2009 CONTENTS Contents i List of Figures v List of Tables vii Acknowledgments ix Abstract xi 1 Introduction 1 1.1 Gamma-raybursthostgalaxies . ....... 1 1.1.1 FirstObservations . .... ... .... .... .... ... .... .. ... 1 1.1.2 Progenitors ................................... 3 1.1.3 Hostgalaxies .................................. 4 1.2 Submillimetergalaxies . ....... 7 1.2.1 Firstdiscovery ................................ .. 7 1.2.2 Leapforward:preciselocalisations . ......... 8 1.2.3 The nature of submillimeter galaxies . ........ 10 1.3 Thisthesis ...................................... ... 10 2 Observations at radio wavelengths 11 2.1 Radioemission ................................... ... 11 2.1.1 Free-FreeEmission . .... ... .... .... .... ... .... .. ... 11 2.1.2 SynchrotronEmission . ... 12 2.1.3 Whyradio? .................................... 13 2.2 Radiointerferometry . ...... 16 2.3 Datareduction................................... .... 18 2.3.1 Datapreparation ............................... .. 18 2.3.2 Flaggingbaddata............................... .. 19 2.3.3 Calibration................................... .. 20 2.3.4 Imaging ...................................... 22 2.3.5 Dataanalysis .................................. 23 2.4 RadiosurveyofGRBhosts. ..... 25 2.4.1 Sample....................................... 25 2.4.2 DataReductionandAnalysis . .... 26 2.4.3 Results....................................... 26 i List of Tables 3 Spectral energy distribution modeling 31 3.1 GRASILprinciples ................................ .... 31 3.2 Stellarpopulation............................... ...... 31 3.3 Geometry........................................ .. 32 3.4 Dustandradiativetransfer . ....... 33 3.5 Derivationofgalaxyproperties . ......... 34 4 The nature of GRB-selected submillimeter galaxies: hot andyoung 35 4.1 Introduction .................................... .... 35 4.2 GRASILSEDModeling............................... ... 36 4.3 Results ......................................... .. 37 4.4 Discussion ...................................... ... 39 4.4.1 Solvingthepuzzle .............................. .. 39 4.4.2 ThenatureoftheGRBhosts. ... 41 4.4.3 RejectionofanAGNcontribution . ..... 42 4.4.4 Thegeneralpictureofdustproperties . ........ 43 4.5 Conclusions ..................................... ... 45 4.6 Comparison of our results with the literature . ............ 45 4.6.1 Ages ........................................ 46 4.6.2 Starformationrates .... ... .... .... .... ... .... .. ... 46 4.6.3 Stellarmasses ................................. .. 46 4.6.4 Dustproperties ................................ .. 46 5 Properties of the host galaxy and the immediate environmentofGRB980425 49 5.1 Introduction .................................... .... 49 5.2 Data............................................ 50 5.3 SEDModeling..................................... .. 55 5.4 Results ......................................... .. 55 5.4.1 StellarMasses................................. .. 55 5.4.2 StarFormationRates. ... 55 5.4.3 DustProperties ................................ .. 57 5.5 Discussion ...................................... ... 58 5.5.1 TheHostGalaxy ................................. 58 5.5.2 RadioDetection................................ .. 59 5.5.3 WRRegion .................................... 60 5.6 Conclusions ..................................... ... 61 6 Cosmic evolution of submillimeter galaxies 63 6.1 Introduction .................................... .... 63 6.2 Sample .......................................... 65 6.3 Methodology ..................................... .. 65 6.3.1 SEDmodeling................................... 65 6.3.2 Volumedensities ............................... .. 68 6.4 Results ......................................... .. 69 6.5 Discussion ...................................... ... 70 6.5.1 SpectralenergydistributionsofSMGs . ........ 70 6.5.2 PropertiesofSMGs.............................. .. 71 6.5.3 Contribution to stellar mass assembly . ........ 74 ii BIBLIOGRAPHY 6.5.4 Sourceofemission .............................. .. 78 6.5.5 Comparison of our results with the literature . .......... 80 6.6 Conclusions ..................................... ... 81 6.7 Longtablesandfigures... .... ... .... .... .... ... .... ..... 82 7 Formation of stars and dust in submillimetergalaxies at redshifts z > 4 95 7.1 Introduction .................................... .... 95 7.2 Sample .......................................... 96 7.3 SEDFittingandResults .. .... ... .... .... .... ... .... ..... 98 7.4 Discussion ...................................... ... 98 7.4.1 Formation of stars in z > 4 SMGs........................ 98 7.4.2 Producers of dust in z > 4 SMGs........................ 101 7.4.3 The IR-radio correlation at z > 4 ........................ 104 7.4.4 Gas-to-dust ratio at z > 4 ............................ 104 7.5 Conclusions ..................................... 104 7.6 IMFandDustYieldCalculations . ....... 105 8 Conclusions 107 8.1 Summary......................................... 107 8.2 Outlook......................................... 108 A Acronyms 109 B Reduction scripts 111 B.1 Entirereductionscript/logfile . ......... 111 B.2 Imagingscript................................... .... 121 C Co-author statements 125 Bibliography 131 iii LIST OF FIGURES 1.1 StarformationdensityoftheUniverse . .......... 2 1.2 Distribution of GRBs on the sky . ....... 3 1.3 DurationofGRBs .................................. ... 4 1.4 SpectrumofSN-relatedGRB030329 . ....... 5 1.5 JamesClerkMaxwellTelescope . ....... 6 1.6 SCUBApixellayout................................ .... 7 1.7 Atmospheric transmission and SCUBA filters . .......... 8 1.8 K-correction at the submillimeter wavelengths . ......... 9 2.1 Radiosky........................................ .. 12 2.2 AustraliaTelescopeCompactArray . ........ 13 2.3 Powerpatternofabeam ............................. .... 14 2.4 Radioaperturesynthesis . ....... 15 2.5 Cleanmap,beamanddirtymap. ..... 16 2.6 Comparison of SFRs derived from radio and IR emission . ........... 29 3.1 Starformationhistoryofagalaxy. ......... 32 3.2 GeometryofagalaxyinGRASIL . ..... 33 4.1 Spectral energy distribution of submm/radio bright GRB hosts .......... 38 4.2 Dust temperature as a function of infrared luminosty . ............. 43 5.1 6cmATCAimageofthehostofGRB980425 . ..... 51 5.2 Multi-wavelength mosaic of images of the host of GRB 980425........... 52 5.3 Spectral energy distribution of the host of GRB 980425 . .............. 56 6.1 MedianspectralenergydistributionofSMGs . ........... 66 6.2 Redshift evolution of the properties of SMGs . ........... 67 6.5 Radio luminosity density as a function of infrared luminosityofSMGs . 77 6.6 Redshift evolution of IR-radio correlation . ............. 78 6.7 SpectralenergydistributionsofSMGs . .......... 85 7.1 Spectral energy distributions of z > 4 SMGs...................... 97 7.2 IR-radio correlation up to redshifts z ∼ 5 ....................... 102 v LIST OF TABLES 2.1 Observation log for radio GRB host project . .......... 27 2.2 Radio fluxes and star formation rates of GRB hosts . ........... 28 4.1 Properties of submm/radio bright GRB hosts . .......... 40 5.1 Photometry of the GRB 980425 host and the WR region . ......... 53 5.2 Properties of the GRB 980425 host its WR region . .......... 54 6.1 MeanvaluesforSMGsinredshiftbins . ........ 71 6.2 PropertiesofSMGs ................................ .... 83 7.1 Properties of z > 4 SMGs................................. 99 7.2 Stellar dust yields required to explain dust in z > 4 SMGs.............. 100 vii ACKNOWLEDGMENTS I dedicate this PhD thesis to my wonderful wife Joanna Baradziej. I would like to thank her for her love, support and understanding during these three years. I would like to express my deep gratitude to my supervisors Jens Hjorth and Darach Watson for so much help, for guiding me through scientific world, for inspiration, and for invaluable discussions and comments (also Darach’s comments on Jens’ desk). Without you this thesis would not have been possible. I am grateful to José María Castro Cerón for numerous inspiring discussions; to Thomas Greve for help and comments on submillimeter galaxies and CSO data; to Daniele Malesani for extensive help with acquisition and interpretation of optical data; to Atish Kamble for taking care of GMRT observations; to Robert Reinfrank for operational introduction to ATCA, help with ATCA data reduction and willingness to spend significant time on observing for me; to Alexander van der Horst for help with WSRT data reduction; and to Jorge Iglesias-Páramo and Laura Silva for providing their SED models. I would like to thank all people at Dark Cosmology Centre for creating so inspiring and lively environment. Special thanks to Andrew Zirm, Justyn Maund and Robert Reinfrank for proofreading my thesis. Finally, thanks to my friends and my family, parents, parents-in-law, Anita, Jurek, Paweł and Gosia for their support. I would like to acknowledge the financial support from the Faculty of Science, University of Copenhagen and Dark Cosmology Centre. ix ABSTRACT One of the aspects of the understanding of the Universe evolution
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