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From: Christopher Dessert <dessert@umich.edu> Date: Thu, 9 May 2019 15:59:49 -0400 Subject: Source extraction regions with nearby contaminating sources To: Jan-Uwe Ness <xmmhelp@sciops.esa.int>
--0000000000002ecd08058879e52b Content-Type: text/plain; charset="UTF-8" Hi, I'm extracting spectra around a bright source in the soft X-rays to perform a search for hard X-rays from the source (specifically, the target of observation ID 0165971901). However, when I run edetect_chain I find that there is a contaminating point source about 47 arcseconds away. This will definitely contribute to the flux in the source extraction region (for example, if I extract within 50 arcseconds, approximately the 90% extraction radius). How should I go about keeping the maximum source flux but also not extracting much of the contamination? I cannot figure out how to extract from a region that is a circle around the source minus a circle around the contamination. I'm also not sure if it is known how to calculate the encircled energy fraction with this extraction region. Is there a tool I can use here? Best, Chris --0000000000002ecd08058879e52b Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr"><div>Hi,</div><div><br></div><div>I'm extracting spect= ra around a bright source in the soft X-rays to perform a search for hard X= -rays from the source (specifically, the target of observation ID 016597190= 1). However, when I run edetect_chain I find that there is a contaminating = point source about 47 arcseconds away. This will definitely contribute to t= he flux in the source extraction region (for example, if I extract within 5= 0 arcseconds, approximately the 90% extraction radius). How should I go abo= ut keeping the maximum source flux but also not extracting much of the cont= amination? I cannot figure out how to extract from a region that is a circl= e around the source minus a circle around the contamination. I'm also n= ot sure if it is known how to calculate the encircled energy fraction with = this extraction region. Is there a tool I can use here?</div><div><br></div= ><div>Best,</div><div><br></div><div>Chris<br></div></div> --0000000000002ecd08058879e52b--
From: Lucia Ballo <xmmhelp@sciops.esa.int> To: dessert@umich.edu Subject: Re: Source extraction regions with nearby contaminating sources (PR#84922) Date: Mon May 13 16:02:26 2019
Dear Chris, > extraction radius). How should I go about keeping the maximum source flux > but also not extracting much of the contamination? I cannot figure out how > to extract from a region that is a circle around the source minus a circle > around the contamination. I'm also not sure if it is known how to calculate SAS supports not only a number of different shapes but also a combination of them. For a description of the allowed shapes, of the syntax rules the boolean selection expression must adhere to, as well as example expressions, please consult the documentation of the SAS package selectlib: https://xmm-tools.cosmos.esa.int/external/sas/current/doc/selectlib/index.html For example, the following expression: circle(x_src,y_src,r_src,X,Y).and..not.circle(x_cont,y_cont,r_cont,X,Y) should select all the events in a circle of radius r_src centered in (x_src,y_src) but excluding all the events in a circle of radius r_cont centred in (x_cont,y_cont) We recommend that whenever you create a spatial filter, before you create a spectrum from it, it might be good to create an image to check that you indeed selected the correct spatial region. > around the contamination. I'm also not sure if it is known how to calculate > the encircled energy fraction with this extraction region. Is there a tool > I can use here? To calculate the encircled energy correction, the SAS task arfgen uses a formulation of the PSF (known as the ELLBETA model) that is valid for all extraction region shapes. In case of complex extraction regions (as yours), you need to tell arfgen where the centre of the source is actually located (using the parameters "sourcex" and "sourcey") so that it can calculate the encircled energy correction properly. To do this, you have to call arfgen with the parameter withsourcepos=true specifying coordinate system through the parameter "sourcecoords" (four coordinate systems can be used: EQPOS, POS, TEL and DET). For more information, please have a look to the arfgen documentation: https://xmm-tools.cosmos.esa.int/external/sas/current/doc/arfgen/index.html I hope that this can help you; otherwise please do not hesitate to contact us again. With kind regards Lucia
From: Christopher Dessert <dessert@umich.edu> Date: Mon, 13 May 2019 11:05:18 -0400 Subject: Re: Source extraction regions with nearby contaminating sources (PR#84922) To: Lucia Ballo <xmmhelp@sciops.esa.int>
--0000000000003863b90588c63f33 Content-Type: text/plain; charset="UTF-8" Thanks Lucia--this is very detailed and helpful. I did not know about selectlib. Best, Chris On Mon, May 13, 2019 at 10:07 AM Lucia Ballo <xmmhelp@sciops.esa.int> wrote: > Dear Chris, > > > extraction radius). How should I go about keeping the maximum source flux > > but also not extracting much of the contamination? I cannot figure out > how > > to extract from a region that is a circle around the source minus a > circle > > around the contamination. I'm also not sure if it is known how to > calculate > > SAS supports not only a number of different shapes but also a combination > of > them. > For a description of the allowed shapes, of the syntax rules the boolean > selection expression must adhere to, as well as example expressions, > please > consult the documentation of the SAS package selectlib: > > > https://xmm-tools.cosmos.esa.int/external/sas/current/doc/selectlib/index.html > > For example, the following expression: > > circle(x_src,y_src,r_src,X,Y).and..not.circle(x_cont,y_cont,r_cont,X,Y) > > should select all the events in a circle of radius r_src centered in > (x_src,y_src) but excluding all the events in a circle of radius r_cont > centred in (x_cont,y_cont) > > We recommend that whenever you create a spatial filter, before you create > a spectrum from it, it might be good to create an image to check that you > indeed selected the correct spatial region. > > > > > around the contamination. I'm also not sure if it is known how to > calculate > > the encircled energy fraction with this extraction region. Is there a > tool > > I can use here? > > To calculate the encircled energy correction, the SAS task arfgen uses a > formulation of the PSF (known as the ELLBETA model) that is valid for all > extraction region shapes. > In case of complex extraction regions (as yours), you need to tell arfgen > where the centre of the source is actually located (using the parameters > "sourcex" and "sourcey") so that it can calculate the encircled energy > correction properly. To do this, you have to call arfgen with the parameter > > withsourcepos=true > > specifying coordinate system through the parameter "sourcecoords" (four > coordinate systems can be used: EQPOS, POS, TEL and DET). > For more information, please have a look to the arfgen documentation: > > https://xmm-tools.cosmos.esa.int/external/sas/current/doc/arfgen/index.html > > > I hope that this can help you; otherwise please do not hesitate to contact > us again. > > With kind regards > Lucia > > This message is intended only for the recipient(s) named above. It may > contain proprietary information and/or > protected content. Any unauthorised disclosure, use, retention or > dissemination is prohibited. If you have received > this e-mail in error, please notify the sender immediately. ESA applies > appropriate organisational measures to protect > personal data, in case of data privacy queries, please contact the ESA > Data Protection Officer (dpo@esa.int). > > > --0000000000003863b90588c63f33 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr"><div>Thanks Lucia--this is very detailed and helpful. I di= d not know about selectlib.</div><div><br></div><div>Best,</div><div><br></= div><div>Chris<br></div></div><br><div class=3D"gmail_quote"><div dir=3D"lt= r" class=3D"gmail_attr">On Mon, May 13, 2019 at 10:07 AM Lucia Ballo <<a= href=3D"mailto:xmmhelp@sciops.esa.int">xmmhelp@sciops.esa.int</a>> wrot= e:<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0= .8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Dear Chris,<b= r> <br> > extraction radius). How should I go about keeping the maximum source f= lux<br> > but also not extracting much of the contamination? I cannot figure out= how<br> > to extract from a region that is a circle around the source minus a ci= rcle<br> > around the contamination. I'm also not sure if it is known how to = calculate<br> <br> SAS supports not only a number of different shapes but also a combination o= f<br> them.<br> For a description of the allowed shapes, of the syntax rules the boolean <b= r> selection expression must adhere to, as well as example expressions, please= <br> consult the documentation of the SAS package selectlib:<br> <br> <a href=3D"https://xmm-tools.cosmos.esa.int/external/sas/current/doc/select= lib/index.html" rel=3D"norefer
From: Christopher Dessert <dessert@umich.edu> Date: Wed, 5 Jun 2019 05:15:06 -0400 Subject: Re: Source extraction regions with nearby contaminating sources (PR#84922) To: Lucia Ballo <xmmhelp@sciops.esa.int>
--0000000000001cc64e058a900829 Content-Type: text/plain; charset="UTF-8" Hi Lucia, Thanks for your previous help. I have a followup question. I am attempting to input the source center coordinates in arfgen as mentioned above. To do this, I was using the coordinates directly listed in the region file (RA and Dec corresponding to the TCRVL2 and TCRVL3 keywords). However when I do this (i.e., using these RA and Dec with sourcecoords=eqpos) the effective area is several orders of magnitude too small. I discovered that these are somehow in the wrong coordinate system , because if I use ds9 to tell me these coordinates in ICRS, I get different RA and Dec. If I use these new RA and Dec with arfgen sourcecoords=eqpos, the effective area comes out correctly. I'm looking at several sources and would prefer not to do this manually in each case. How can I convert the RA and Dec in the region file to the ICRS RA and Dec? Or what options do I need to use to use the region RA and Dec directly with arfgen? Best, Chris On Mon, May 13, 2019 at 11:05 AM Christopher Dessert <dessert@umich.edu> wrote: > Thanks Lucia--this is very detailed and helpful. I did not know about > selectlib. > > Best, > > Chris > > On Mon, May 13, 2019 at 10:07 AM Lucia Ballo <xmmhelp@sciops.esa.int> > wrote: > >> Dear Chris, >> >> > extraction radius). How should I go about keeping the maximum source >> flux >> > but also not extracting much of the contamination? I cannot figure out >> how >> > to extract from a region that is a circle around the source minus a >> circle >> > around the contamination. I'm also not sure if it is known how to >> calculate >> >> SAS supports not only a number of different shapes but also a combination >> of >> them. >> For a description of the allowed shapes, of the syntax rules the boolean >> selection expression must adhere to, as well as example expressions, >> please >> consult the documentation of the SAS package selectlib: >> >> >> https://xmm-tools.cosmos.esa.int/external/sas/current/doc/selectlib/index.html >> >> For example, the following expression: >> >> circle(x_src,y_src,r_src,X,Y).and..not.circle(x_cont,y_cont,r_cont,X,Y) >> >> should select all the events in a circle of radius r_src centered in >> (x_src,y_src) but excluding all the events in a circle of radius r_cont >> centred in (x_cont,y_cont) >> >> We recommend that whenever you create a spatial filter, before you create >> a spectrum from it, it might be good to create an image to check that you >> indeed selected the correct spatial region. >> >> >> >> > around the contamination. I'm also not sure if it is known how to >> calculate >> > the encircled energy fraction with this extraction region. Is there a >> tool >> > I can use here? >> >> To calculate the encircled energy correction, the SAS task arfgen uses a >> formulation of the PSF (known as the ELLBETA model) that is valid for all >> extraction region shapes. >> In case of complex extraction regions (as yours), you need to tell arfgen >> where the centre of the source is actually located (using the parameters >> "sourcex" and "sourcey") so that it can calculate the encircled energy >> correction properly. To do this, you have to call arfgen with the >> parameter >> >> withsourcepos=true >> >> specifying coordinate system through the parameter "sourcecoords" (four >> coordinate systems can be used: EQPOS, POS, TEL and DET). >> For more information, please have a look to the arfgen documentation: >> >> >> https://xmm-tools.cosmos.esa.int/external/sas/current/doc/arfgen/index.html >> >> >> I hope that this can help you; otherwise please do not hesitate to >> contact >> us again. >> >> With kind regards >> Lucia >> >> This message is intended only for the recipient(s) named above. It may >> contain proprietary information and/or >> protected content. Any unauthorised disclosure, use, retention or >> dissemination is prohibited. If you have received >> this e-mail in error, please notify the sender immediately. ESA applies >> appropriate organisational measures to protect >> personal data, in case of data privacy queries, please contact the ESA >> Data Protection Officer (dpo@esa.int). >> >> >> --0000000000001cc64e058a900829 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr"><div>Hi Lucia,</div><div><br></div><div>Thanks for your pr= evious help. I have a followup questi
From: Lucia Ballo <xmmhelp@sciops.esa.int> To: dessert@umich.edu Subject: Re: Source extraction regions with nearby contaminating sources (PR#84922) Date: Fri Jun 7 15:35:39 2019
Dear Chris, In order to better assist you, could you please tell me what region file are you referring to, and clarify me how are you using the TCRVLs keywords reported in the event files to derive the coordinates of your source? Many thanks in advance. With kind regards, Lucia