Archive for the ‘引力波’ Category

PRL:一个引力波速度测定的新方法

星期日, 十二月 18th, 2016

First successful detection of gravitational waves (GW) by LIGO/Virgo opened up a new window on the Universe and gave us unprecedented possiblities of testing gravity. In particular the issue of the speed of gravity, in General   Relativity  equal to the speed of light, became now accessible for experimental tests. Any observational clue that gravitational waves propagate with speed   different from c would mark the breakdown of General Relativity.

In this paper we propose a new method to measure the speed of gravity   assuming that strongly lensed gravitational signal accompanied by its electromagnetic (EM) counterpart   could be detected. The method is based on measuring the difference between strong lensing   time delays registered in GW and EM. The differential setting of our method makes it robust and free from the intrinsic time delays in the source (i.e. different emission times of GW and EM signal).

Strongly lensed GW signals are expected to be registered by the next   generation of interferometric detectors like the Einstein Telescope.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.091102

arXiv:1612.04095

gw-em 测试流程

星期六, 二月 22nd, 2014

1. 根据f-function 产生 injection 的位置: gendist

2. 根据 gw模型产生injection 的波形+data analysis : LAL

3. play with  posterior samples and f-fuunction : hist2d + greedy

LAL 学习

星期二, 六月 18th, 2013

LAL 学习
https://www.lsc-group.phys.uwm.edu/daswg/projects/lalsuite.html

LAAC Data Analysis Training
LALSuite
installing LAL and LALApps
LALSuite Git
LALSuite is comprised of the following components
LAL: Core gravitational wave analysis routines
LALFrame: LAL wrapping of the LIGO/Virgo Frame library
LALMetaIO:LAL wrapping of the MetaIO LIGO_LW XML library
LALXML:LAL wrapping of the libxml2 XML library, currently unused
LALSimulation:LAL routines for gravitational waveform and noise generation
LALBurst:LAL routines for burst gravitational wave data analysis
LALInspiral:LAL routines for inspiral and ringdown CBC gravitational wave data analysis
LALPulsar:LAL routines for pulsar and continuous wave gravitational wave data analysis
LALInference:LAL routines for Bayesian inference data analysis
LALStochastic:LAL routines for stochastic background gravitational wave data analysis
LALApps: Collection of gravitational wave data analysis codes and pipelines utilising the LAL libraries

cbc code 执行命令
https://www.lsc-group.phys.uwm.edu/ligovirgo/cbcnote/BayesianReview/InspnestDocs

universe = standard
executable = lalapps_inspnest
arguments = ” -i LALLIGO -I H1 -C test –inj test_injection.xml -o test_0.dat –srate 2048 –Nsegs 10 –length 100 –Nlive 1000 –Nmcmc 200 –verbose”
error = lalapps_inspnest$(Process).err
output = lalapps_inspnest$(Process).out
log = mycode.log
notification = never
queue

安装 LALSuite
https://www.lsc-group.phys.uwm.edu/daswg/docs/howto/lal-install.html
某机器上第一次安装
先安装有一些别的软件确保LALSuite安装
必须有些手动操作设置    To setup your environment to use the newly-built LAL
分别安装LALSuite 里面的每个包  (顺序和网站上说的不同有时需要不同,因为包的依赖问题,要有耐心测试。。。)
LAL
LALFrame
LALMetalO
LAMXML
LALSimulation
LALBurst
LALPulsar
LALInspiral
LALInference
LALApps   如果不是需要远程登陆本机器操作, 就不用  –enable-condor

最后 别忘了 把 source ${LSCSOFT_ROOTDIR}/etc/lscsoftrc 加到     .bash_profile  里面!

安装LALSuite  note  from Matt
cloned the lalsuite directory (e.g. using “git clone xilong.fan@ligo-vcs.phys.uwm.edu:/usr/local/git/lalsuite.git”)
installed all the parts of lalsuite (lal, lalmetaio, lalxml,lalsimulation, lalinspiral, lalburst, lalpulsar, lalstochastic, lalinference)
checked-out the lalinference_burst branch using “git branch –track lalinference_burst origin/lalinference_burst”
git checkout lalinference_burst

–If that’s what you’ve done then you should currently be in the lalinference_burst branch. You can check what branch you’re in by typing “git branch” and it will list the branches – there will be a * next to the name of the branch that you are in.
–If you want to run codes that have been developed in this branch then you should probably reinstalled all of lalsuite from this branch. So, you should perform “make uninstall” and “make distclean” in all the parts of lalsuite, and then reinstall all of them.

Note: Having the release versions of LALSuite installed from MacPorts will lead to build errors if you try and build LALSuite from the git repository. If you are planning on building LALSuite from git do not installed these ports.

如果安装了怎么办?
卸载!

fantekiMacBook-Pro:~ fanf$ sudo port uninstall lalapps
fantekiMacBook-Pro:~ fanf$ sudo port uninstall LALStochastic
sudo port uninstall LALApps
sudo port uninstall LALInference
sudo port uninstall LALStochastic
sudo port uninstall LALInspiral
sudo port uninstall LALPulsar
sudo port uninstall LALBurst
sudo port uninstall LALSimulation
sudo port uninstall LALMetaiO
sudo port uninstall LALXML
sudo port uninstall LALFrame
sudo port uninstall LAL