TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1514 SUBJECT: GRB020813: VRI Decay Slopes DATE: 02/08/21 03:19:31 GMT FROM: Derek Fox at CIT <derekfox@astro.caltech.edu> Mike Gladders (Carnegie Observatories) and Pat Hall (Princeton/Catolica) report: "The photometric data reported previously by us yield the following decay slopes for the OT of GRB020813. The decay slopes in various filters implied by the data from August 13UT are: I: -0.677+-0.016 (all data August 13UT) I: -0.76+-0.03 (only UT>6.5, to match R&V time range) R: -0.82+-0.06 V: -0.75+-0.05 "These data are consistent with the same power law decay in all three filters in the time interval 6.5<UT<7.5, and are consistent with the discussion in GCN #1476. Based purely on these data, the two earlier I-band data points are 0.045+-0.015 magnitudes too faint, implying that a break in the decay has already occurred by ~4 hours after the GRB event. This is again consistent with GCN #1476. "Also, the data yield decay slopes between August 13 and 14 UT of -0.96+-0.04,-1.02+-0.01,-1.01+-0.02 in I,R and V respectively. These values lie midway between the early time slope (above, and GCN #1476), and the later time slope of -1.4+-0.02 (August 13.99 UT to August 16.03 UT, GCN #1500). The slope derived here is nominally inconsistent with the decay reported in GCN #1491 (-1.44) over a time window similar to the data reported here. However, allowing for the uncertainties of the three data points in GCN #1491 yields a decay slope of -1.3+-0.30, consistent with the results reported here. "It thus appears that the decay slope of this OT has continued to steepen with time, rather than having undergone a simple break." -=- MIME -=- This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. Send mail to mime@docserver.cac.washington.edu for more info. --1539329202-1703855553-1029736956=:1863 Content-Type: TEXT/PLAIN; charset=US-ASCII Hi Derek: I've got a favor to ask: could you fire in a couple more GCN on my behalf? I've sent email to Scot B. asking to be a subscriber but sitll haven't heard back from him, and want to get this on its way. The two GCN are attached, and should be titled: "GRB020813: Magellan BVRI Photometry" and "GRB020813: VRI Decay Slopes" I'm still working up a package of data for release to the community: once I have everything assembled and in an accesible place I guess I'll have to put out one more GCN to let everyone know where it is. Since I got 50+ data points on this thing I expect people will want to use the data? Hopefully I will have hear back from the GCN people by then though and won't have to pester you again ;-) Thanks much in advance (presumtuously assuming you will help;-) Cheers, Mike --1539329202-1703855553-1029736956=:1863 Content-Type: TEXT/plain; name="GCNphot.txt" Content-Transfer-Encoding: BASE64 Content-ID: <Pine.LNX.4.44.0208182302360.1863@seydlitz.ociw.edu> Content-Description: Content-Disposition: attachment; filename="GCNphot.txt" TWlrZSBHbGFkZGVycyAoQ2FybmVnaWUgT2JzZXJ2YXRvcmllcykgYW5kIFBh dCBIYWxsIChQcmluY2V0b24vQ2F0b2xpY2EpIHJlcG9ydDoNCg0KQSB0b3Rh bCBvZiAzNyBpbWFnZXMgKDE2IGluIEksIDEwIGluIFIsIDExIGluIFYpIG9m IHRoZSBPVCBhc3NvY2lhdGVkDQp3aXRoIEdSQjAyMDgxMyB3ZXJlIGFjcXVp cmVkIHdpdGggdGhlIEJhYWRlIDYuNW0gKE1hZ2VsbGFuIEkpDQp0ZWxlc2Nv cGUgYW5kIFRFSzUgY2FtZXJhIG9uIHRoZSBuaWdodCBvZiBBdWd1c3QgMTMg VVQsIHVuZGVyDQpjb25kaXRpb25zIG9mIGV4Y2VsbGVudCBzZWVpbmcgYW5k IHRyYW5zcGFyZW5jeS4gQSBmdXJ0aGVyIDE1IGltYWdlcw0KKDUgaW4gSSwg NCBlYWNoIGluIEJSIGFuZCAyIGluIFYpIHdlcmUgYWNxdWlyZWQgb24gdGhl IG5pZ2h0IG9mIEF1Z3VzdA0KMTQgVVQsIHVuZGVyIHNpbWlsYXIgY29uZGl0 aW9ucywgdGhvdWdoIHdpdGggc29tZSBwb3NzaWJsZSBjaXJydXMuDQoNCkEg cHJlbGltaW5hcnkgYW5hbHlzaXMgb2YgdGhlc2UgaW1hZ2VzIHlpZWxkcyB0 aGUgbWFnbml0dWRlcyBiZWxvdyBmb3INCnRoZSBPVCBhc3NvY2lhdGVkIHdp dGggR1JCMDIwODEzLiBNYWduaXR1ZGVzIGhhdmUgYmVlbiBjb21wdXRlZA0K ZGlmZmVyZW50aWFsbHkgcmVsYXRpdmUgdG8gYXBwcm94aW1hdGVseSAyMCBz dGFycyBzdHJhZGRsaW5nIHRoZQ0KbWFnbml0dWRlIHJhbmdlIG9mIE9ULCBs b2NhdGVkIGluIHRoZSBzYW1lIGZpZWxkICgyeDIgYXJjbWludXRlcykuDQpJ bnRlcm5hbCB1bmNlcnRhaW50aWVzIChlc3RpbWF0ZWQgZnJvbSByZXNpZHVh bHMgaW4gdGhlIGRpZmZlcmVudGlhbA0KY29ycmVjdGlvbnMpIGFyZSBhYm91 dCAwLjAxIG1hZ25pdHVkZXMgb24gQXVndXN0IDEzIFVULCBhbmQgYWJvdXQg MC4wMg0Kb24gQXVndXN0IDE0VVQsIGFuZCB0aGUgc3lzdGVtYXRpYyB1bmNl cnRhaW50eSBpbiB0aGUgY2FsaWJyYXRpb24gb2YNCnRoZSB6ZXJvLXBvaW50 cyBpcyBsZXNzIHRoYW4gMC4wNSBtYWduaXR1ZGVzIGluIG1vc3QgY2FzZXMu IFRoZSBCLWJhbmQNCnplcm8tcG9pbnQsIGVzdGFibGlzaGVkIG9uIEF1Z3Vz dCAxNCBVVCwgbWF5IGJlIGFmZmVjdGVkIGJ5IGxpZ2h0DQpjaXJydXMgb24g dGhlIHNjaWVuY2UgZnJhbWVzLCBhbmQgaXMgcXVlc3Rpb25hYmxlLg0KDQpB dWd1c3QgMTMgVVQ6DQotLS0tLS0tLS0tLS0tDQoNCkktYmFuZDoNCi0tLS0t LS0NCiBVVAlNYWduaXR1ZGUNCiA1Ljc3NDIgMTcuOTEwDQogNS44OTIyIDE3 LjkyOA0KIDYuNjE1MyAxOC4wNjENCiA2Ljc0NjEgMTguMDkwDQogNi43NzMz IDE4LjEwOA0KIDYuNzk4NiAxOC4wNzgNCiA2LjgyMzYgMTguMTA2DQogNi44 NDg2IDE4LjEwNA0KIDcuMDAzNiAxOC4xMzkNCiA3LjI5MzkgMTguMTkyDQog Ny40MjI1IDE4LjIwOA0KIDcuNTQwMCAxOC4yNDkNCiA3LjU2NTAgMTguMjQx DQogNy41OTAwIDE4LjIzMw0KIDcuNjE1MyAxOC4yMjgNCiA3LjY0MDMgMTgu MjczDQoNClItYmFuZDoNCi0tLS0tLS0NCiBVVAlNYWduaXR1ZGUNCiA2Ljcw NjEgMTguNDkxDQogNi45MTIyIDE4LjUyMA0KIDYuOTQyMiAxOC41MzYNCiA3 LjE0NzggMTguNTc4DQogNy4xNzI4IDE4LjU3OQ0KIDcuMTk3OCAxOC41ODIN CiA3LjIyMjggMTguNTkxDQogNy4zMjIyIDE4LjYwOA0KIDcuMzkyNSAxOC42 MjUNCiA3LjUwODMgMTguNjU0DQoNClYtYmFuZDoNCi0tLS0tLS0NCiBVVAlN YWduaXR1ZGUNCiA2LjY3NjcgMTguODUwDQogNi44ODM2IDE4Ljg4Mg0KIDYu OTczOSAxOC45MTYNCiA3LjA0MDAgMTguOTIyDQogNy4wNjUzIDE4LjkzMA0K IDcuMDkwNiAxOC45MjkNCiA3LjExNTYgMTguOTMyDQogNy4yNjE0IDE4Ljk1 Mw0KIDcuMzU5MiAxOC45ODINCiA3LjQ1MDggMTkuMDAwDQogNy40NzgxIDE4 Ljk5OQ0KDQoNCg0KQXVndXN0IDE0IFVUOg0KLS0tLS0tLS0tLS0tLQ0KDQpJ LWJhbmQ6DQotLS0tLS0tDQogVVQJTWFnbml0dWRlDQogMS4wMDMzIDE5Ljg1 NA0KIDEuMDM0NCAxOS44NjINCiAxLjA1OTQgMTkuODM3DQogMS4wODQ0IDE5 Ljg5MQ0KIDEuMTA5NCAxOS44NDgNCg0KUi1iYW5kOg0KLS0tLS0tLQ0KIFVU CU1hZ25pdHVkZQ0KIDEuMjQ0NyAyMC40MjANCiAxLjI2OTcgMjAuNDExDQog MS4yOTQ3IDIwLjQyMA0KIDEuMzE5NyAyMC40MTkNCg0KVi1iYW5kOg0KLS0t LS0tLQ0KIFVUCU1hZ25pdHVkZQ0KIDEuMzQ4NiAyMC44MDUNCiAxLjM3MzYg MjAuODExDQoNCkItYmFuZDoNCi0tLS0tLS0NCiBVVAlNYWduaXR1ZGUNCiAx LjEzOTcgMjEuMzY1DQogMS4xNjQ3IDIxLjMxNQ0KIDEuMTg5NyAyMS4zNDMN CiAxLjIxNDcgMjEuMzM4DQoNCg0K --1539329202-1703855553-1029736956=:1863 Content-Type: TEXT/plain; 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