The Herschel-SPIRE Legacy Survey (HSLS) The Scientific Goals of a Shallow and Wide Submillimeter Imaging Survey with SPIRE Members of the HSLS Study Team Asantha Cooray1, Steve Eales2, Scott Chapman14, David L. Clements4, Olivier Dor´e5, Duncan Farrah6, Matt J. Jarvis8 Manoj Kaplinghat1, Mattia Negrello3, Alessandro Melchiorri9, Hiranya Peiris11, Alexandra Pope12, Mario G. Santos13, Stephen Serjeant3, Mark Thompson8, Glenn White3,15, Alexandre Amblard1,7, Manda Banerji14, Pier-Stefano Corasaniti16, Sudeep Das17, Francesco de Bernardis9, Gianfranco de Zotti78, Tommaso Giannantonio18,88, Joaquin Gonzalez-Nuevo Gonzalez19, Ali Ahmad Khostovan1, Ketron Mitchell- Wynne1, Paolo Serra1, Yong-Seon Song20, Joaquin Vieira86, Lingyu Wang6, Michael Zemcov86,5 Filipe Abdalla11, Jose Afonso56, Nabila Aghanim49, Paola Andreani21, Itziar Aretxaga84, Robbie Auld2, Maarten Baes85, Andrew Baker58, Denis Barkats68, R. Belen Barreiro60, Nicola Bartolo89, Elizabeth Barton1, Sudhan- shu Barway23, Elia Stefano Battistelli9, Carlton Baugh25, Alexander Beelen49, Karim Benabed49, Andrew Blain86, Joss Bland-Hawthorn46, James J. Bock5,86, J. Richard Bond40, Julian Borrill22,41, Colin Borys67, Alessandro Boselli51, Fran¸cois R. Bouchet79, Carrie Bridge86, Fabrizio Brighenti96, Veronique Buat51, David Buote1, Denis Burgarella51, Robert Bussmann39, Erminia Calabrese9, Christopher Cantalupo22, Raymond Carlberg38, Carla Sofia Carvalho63, Caitlin Casey100, Antonio Cava47,77, Jordi Cepa47, Edward Chapin37, Ranga Ram Chary86, Xuelei Chen87, Natalie Christopher35, Sergio Colafrancesco62,78, Shaun Cole25, Peter Coles2, Alexander Conley93, Luca Conversi74, Jeff Cooke1, Steven Crawford23, Catherine Cress91, Elisa- bete da Cunha95, Gavin Dalton15,35, Luigi Danese19, Helmut Dannerbauer80, Jonathan Davies2, Paolo de Bernardis9, Roland de Putter70, Mark Devlin33, Jose M. Diego60, Herv´eDole49, Marian Douspis49, Joanna Dunkley35, James Dunlop54, Loretta Dunne31, Rolando D¨unner105, Simon Dye2, George Efstathiou102, Ei- ichi Egami39, Taotao Fang1, Patrizia Ferrero47,77, Alberto Franceschini71, Christopher C. Frazer1, David Frayer43, Carlos Frenk25, Ken Ganga53, Rapha¨el Gavazzi79, Jason Glenn93, Yan Gong87, Eduardo Gonzalez- Solares14, Matt Griffin2, Qi Guo25, Mark Gurwell76, Amir Hajian40, Mark Halpern37, Duncan Hanson14, Martin Hardcastle8 Evanthia Hatziminaoglou21, Alan Heavens54, S´ebastien Heinis51, Diego Herranz60, Matt Hilton63, Shirley Ho22, Benne W. Holwerda55, Rosalind Hopwood3, Jonathan Horner99, Kevin Huffenberger64, David H. Hughes84, John P. Hughes58, Edo Ibar83, Rob Ivison54, Neal Jackson48, Andrew Jaffe4, Timo- thy Jenness45, Gilles Joncas75, Shahab Joudaki1, Sugata Kaviraj4, Sam Kim1, Lindsay King14, Theodore Kisner22, Johan Knapen47,77, Alexei Kniazev23, Eiichiro Komatsu34, Leon Koopmans82, Chao-Lin Kuo24, Cedric Lacey25, Ofer Lahav11, Anthony N. Lasenby102, Andy Lawrence54 Myung Gyoon Lee69, Lerothodi L. Leeuw72,73, Louis R. Levenson86, Geraint Lewis46, Nicola Loaring23, Marcos L´opez-Caniego60, Steve Maddox31, Tobias Marriage106, Gaelen Marsden37, Enrique Martinez-Gonzalez60, Silvia Masi9, Sabino Matarrese89, William G. Mathews104, Shuji Matsuura30, Richard McMahon14, Yannick Mellier79, Felipe Menanteau58, Micha lJ. Micha lowski54, Marius Millea98, Bahram Mobasher101, Subhanjoy Mohanty4, Ludovic Montier65, Kavilan Moodley63, Gerald H. Moriarty-Schieven42, Angela Mortier4, Dipak Munshi2, Eric Murphy26, Kirpal Nandra97, Paolo Natoli10, Hien Nguyen5, Seb Oliver6, Alain Omont79, Lyman Page50, Mathew Page66, Roberta Paladini26, Stefania Pandolfi9, Enzo Pascale2, Guillaume Patanchon53, John Peacock54, Chris Pearson15,29, Ismael Perez-Fournon47,77, Pablo G. P´erez-Gonz´alez52, Francesco Piacentini9, Elena Pierpaoli59, Michael Pohlen2, Etienne Pointecouteau65, Gianluca Polenta62, Jason Rawlings66, Erik D. Reese33, Emma Rigby36, Patrick Roche35, Giulia Rodighiero71, Encarni Romero-Colmenero23, Isaac Roseboom6, Michael Rowan-Robinson4, Miguel S´anchez-Portal74, Fabian Schmidt86, Michael Schneider25, Bernhard Schulz67,86, Douglas Scott37, Chris Sedgwick3, Neelima Sehgal94, Nick Seymour66, Blake D. Sherwin50, Jo Short2, David Shupe67, Jonathan Sievers40, Ramin Skibba44, Joseph Smidt1, Anthony Smith6, Daniel J. B. Smith31, Matthew W. L. Smith2, David Spergel27, Suzanne Staggs50, Jason Stevens8, Eric Switzer81, Toshi- nobu Takagi30, Tsutomu Takeuchi103, Pasquale Temi7, Markos Trichas76, Corrado Trigilio78, Katherine Tugwell66, Grazia Umana78, William Vacca92, Mattia Vaccari78, Petri Vaisanen23, Ivan Valtchanov74, Kurt van der Heyden55, Paul P. van der Werf90, Eelco van Kampen21, Ludovic van Waerbeke37, Simona Vegetti57, Marcella Veneziani9, Licia Verde61, Aprajita Verma35, Patricio Vielva60, Marco P. Viero86, Baltasar Vila Vilaro68, Julie Wardlow32, Grant Wilson12, Edward L. Wright28, C. Kevin Xu67,86, Min S. Yun12 Contents Executive Summary 1 1 Introduction 3 2 The Joint Planck/CMB-Herschel Studies 11 2.1 Integrated Sachs-Wolfe (ISW) Effect . ..... 11 2.2 GravitationalLensingoftheCMB. .... 15 2.2.1 What can we learn from CMB lensing and HSLS ? . 16 2.2.2 CMBLensing ............................... 16 2.2.3 Thecross-correlationsignal . ... 16 2.2.4 IR Contamination in CMB Lensing estimators . .... 18 2.3 Sunyaev-Zel’dovich Effect . ... 20 2.3.1 Improving Sunyaev-Zel’dovich Cluster Detection in Planck ...... 20 2.4 Extracting the kinetic SZ and patchy reionization signal ........... 21 3 Cosmological Studies with HSLS 25 3.1 Source Clustering and BAO Cosmology out to z ∼ 2 ............. 25 3.2 PrimordialNon-Gaussianity . .... 31 3.3 Cosmic magnification of sub-mm sources . ..... 34 3.4 Mapping Cosmic Infrared Background Fluctuations with HSLS........ 35 3.4.1 RationaleforaStatisticalApproach. ..... 36 3.4.2 Background Fluctuations from Galaxy Clustering . ....... 36 3.4.3 Detectability of Clustering Fluctuations with Herschel......... 39 3.4.4 Weak Lensing Applications of Fluctuations . ...... 40 3.4.5 Why Herschel is Essential for Background Fluctuations Studies . 40 3.5 Applications related to massive cluster finding . .......... 41 3.6 IGM dust with Herschel-SPIRE Legacy Survey Cross-Correlations . 43 3.7 Applications to 21-cm Measurements . ..... 46 4 The Strongly Lensed Sub-mm Sources 49 4.1 DarkEnergy.................................... 50 4.2 Darkmatterhaloproperties . ... 54 4.3 Fundamental plane of early-type galaxies . ........ 55 4.4 Substructureindarkmatterhalos . ..... 55 4.5 A lensed view of sub-mm galaxies at high redshifts . ........ 56 4.6 Sub-mmfollow-upobservations . .... 59 5 The High-redshift (z > 1) Sub-mm Universe 61 5.1 Overview...................................... 61 5.2 High-z galaxy demographics: What galaxies will be detected by HSLS?... 62 5.2.1 Lensed SMGs as a Probe of Faint z > 5sources ............ 65 5.2.2 How can the redshifts of SMGs be efficiently identified? . ....... 65 5.2.3 High-z QSOs ............................... 67 5.3 HSLS High-z ScienceDrivers........................... 68 5.3.1 Environmental dependence of SFR . 68 5.3.2 Galaxyclustersandproto-clusters . ..... 70 5.3.3 Using lensed SMGs for deep, detailed studies with ALMA ...... 71 5.3.4 Dust properties at high z ......................... 72 5.3.5 Luminosity function evolution . ... 72 6 The Local (z < 1) Sub-mm Universe 73 6.1 Introduction.................................... 73 6.2 Multiwavelength Surveys of the z < 1Universe................. 73 6.3 The Power of a 4000 Square Degree Survey with Herschel . ........ 75 6.3.1 Obscured Star Formation & Galaxy Assembly over 0 <z< 1..... 75 6.3.2 The Local Far-IR Luminosity Function . ... 77 6.3.3 Cold, Luminous Galaxies at Low Redshift . ... 78 6.3.4 Dust in brightest cluster galaxies (BCGs) . ...... 79 6.3.5 The Planck Extragalactic Point Source Population . 79 7 The Search for Rare Objects 81 7.1 ActiveGalacticNucleiandrareobjects . ....... 81 7.1.1 Tracing the build up of the Magorrian relation through optical QSOs 81 7.1.2 Hot and Cold mode accretion and AGN driven feedback . .... 83 7.1.3 High-redshiftquasars . 85 7.1.4 OtherrareAGNpopulations. 85 7.1.5 Radio-loudAGNunification . 86 7.1.6 Blazarphysics............................... 86 7.1.7 Kuiperbeltobjects ............................ 86 7.1.8 Discovery space for new rare object populations . ....... 87 8 Galactic Dust and Stellar Sources 89 8.1 Highgalacticlatitudestarformation . ....... 89 8.2 The properties of dust in the diffuse High Galactic latitudeISM ....... 91 8.3 Dust and the formation of molecular clouds at high latitude ......... 93 8.4 Debris Discs and other stars associated with dust . ......... 94 A Institutional Addresses 109 Executive Summary During the next decade several wide optical and radio surveys will map most of the sky, detect ∼ 109 galaxies, and provide a scientific goldmine for extragalactic astronomers and cosmologists. At the same time, surveys of the cosmic microwave background (CMB) are being carried out over areas ranging from thousands of deg2 to the whole sky (Planck), leading to new information about the Universe since recombination through secondary anisotropies. To fully exploit these large datasets, however, it is vital to have a survey of a similar area in the far-IR/submm waveband. Herschel is the last chance to achieve this, since SPICA (launch date ∼2020) is primarily a spectroscopic mission and will not have coverage at λ> 200 µm, and there are no other missions planned for the foreseeable future. We propose the Herschel-SPIRE Legacy Survey (HSLS), a project using SPIRE that will cover 4000 deg2, one tenth of the whole sky and one