July 4 th, 20061/5 Highlights from the LIGO-Virgo F2F Highlights from the LIGO-Virgo F2F and consequences for the DA groups A.Viceré

July 4 th, 20062/5 Highlights from the LIGO-Virgo F2F Recall the LIGO-Virgo MoU implications Scope of the agreement Exclusive: all the data analysis activity will take place under this umbrella It is not a merger: the Virgo project and the LSC remain independent Joint DA groups will be set up; they propose and carry on the science program Implementation phases Upon MoU signature a transition period begins The joint groups are formed for each of the four source classes Full exchange of information, no exchange of data except limited datasets Start of data exchange depends on Virgo sensitivity progress Each data analysis group will have to set its goals When a group declares that joint activity can start, it starts for ALL the DA groups Organizational framework Joint working groups with one LSC and one Virgo chair, plus co-chairs LIGO co-chairs are currently equivalent to the chairs. Ideally, Virgo co-chairs should be both data analysis and detector experts All analysis projects are to be affiliated with at least one working groups The joint groups are the place where all the DA has to be reported There can be several analysis projects addressing the same search May use different methods or tools Need to cross-check the results, resolve discrepancies if any

July 4 th, 20063/5 Highlights from the LIGO-Virgo F2F How to do science? Data quality, calibration, noise, vetoes Not trivial to work using data of the other experiment! Many issues, some general, some search specific. Need good contact points Covering the physics Each group maintains a list of searches to be performed Not all developed at the same level in LSC and in Virgo Example; the CB group is just starting to address binary BH searches For each search, we can also have multiple methods Example: the burst group develops multiple event trigger generators! Putting LSC’s and Virgo together, what is the extent of complementary/redundancy? For some search, it can make sense to avoid duplication Example: Virgo pulsar group searches a wider spin-down parameter space, at a lower sensitivity than the LSC, which searches over a more restricted spin-down range Anyway experience from both collaborations, for instance for veto studies, are needed for ANY search if it has to be meaningful, regardless of the balance in parties involvment Methods/code cross checking No human resources in Virgo to undertake extensive code reviews! High level flow diagrams to let each party understand what the other is doing Repository of the parameters (configuration files) used for searches Check-points for intermediate results (spectral densities? Event rates?)

July 4 th, 20064/5 Highlights from the LIGO-Virgo F2F Organizational/technical consequences Joint Working Groups functioning The JWG will run by (probably) weekly telecons At these venues, all the activities need to be reported For some groups they can be very numerous! How to deal with this issue? Sub-groups meetings + reports at plenary telecons could be a solution Most of what is done now in Virgo becomes part of the JWG activity, not all We reserve the possibility of meeting focused on Virgo activity (open to LSC people) Detector characterization, veto development, pipeline development may be the topics LSC experts to be involved in the local (veto at least) activity The converse is needed: Virgo people learning about the LIGO machines Data sharing/replication across the Atlantic It is urgent to understand how the exchange will take place Which metadata/indexes are required? Which naming conventions? Which tools? One of the first goals of the Joint Computing and Software committee? Software sharing The LSC publishes LAL and LALapps on the web, including read-only access to the CVS Each physics groups maintains also other codes Virgo physics groups moving toward making available their code as well Portable package set (VCS) to be made available to the LIGO community It is desirable to open read-only CVS access as well

July 4 th, 20065/5 Highlights from the LIGO-Virgo F2F Next actions Continue the test studies Study of the 3 hours well advanced The technical goals were reached More extensive studies require more data exchanges Goal: assessment of methods for coincidence and coeherent analysis Possible as soon as Virgo starts weekend data taking sessions Brace for the start of real data analysis Upon MoU signature, the current LIGO-Virgo group ends, physics groups start Not tomorrow! Still a few LIGO-Virgo telecons Start talking about big things (detection protocols, search vs upper limits).. … and small things (websites, e-logs. Large groups need good bookeeping). Prepare “white papers” from the physics groups Repository for The list of searches performed The methods adopted, described summarily, with references. The people involved (leaders, contacts)

July 4 th, 20066/5 Highlights from the LIGO-Virgo F2F To know more Website of the F2F meeting Slides presented Views from the LSC groups are particularly interesting, see slides by Erik Katsavounidis (LSC burst group) Patrick Brady (LSC inspiral group) Minutes (LIGO-Virgo password)