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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

21113 results found.

  1. LIGO/Virgo S200225q: upper limits from AGILE/MCAL observations
  2. LIGO/Virgo S200225q: No counterpart candidates in HAWC observations
  3. LIGO/Virgo S200225q: Global MASTER-Net observations report
  4. LIGO/Virgo S200224ca: No counterpart candidates in Fermi-LAT observations
  5. LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
  6. LIGO/Virgo S200219ac: No counterpart candidates from Nanshan/NEXT observations
  7. LIGO/Virgo S200224ca: upper limits from AGILE/GRID observations
  8. GRB 200224A: RATIR Optical Observations and Confirmation of the Afterglow
  9. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  10. LIGO/Virgo S200224ca: upper limits from AGILE/MCAL observations
  11. LIGO/Virgo S200224ca: Global MASTER-Net observations report
  12. GRB 200224A: Swift/UVOT Detection
  13. GRB 200224A: Tautenburg observations
  14. GRB 200224A: BOOTES-1 and 1.5m OSN optical observations
  15. Fermi trigger No 604213554: Global MASTER-Net observations report
  16. Swift GRB200224.14: Global MASTER-Net observations report
  17. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
  18. LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
  19. LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
  20. GRB 200219C: OAJ afterglow confirmation
  21. GRB 200219A: UVOT Upper Limits
  22. GRB 200219C: Mondy and TSHAO optical observations
  23. GRB 200219C: Nanshan/NEXT optical upper limit and possible host galaxy from PanSTARRS
  24. LIGO/Virgo S200219ac: No counterpart candidates in KAIT observations
  25. Fermi trigger No 603949983: Global MASTER-Net observations report
  26. GRB 200219C: Swift-XRT afterglow detection
  27. GRB 200219C: DDOTI Observations
  28. LIGO/Virgo S200213t: Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
  29. GRB 200219C: Tiled Swift observations
  30. LIGO/Virgo S200219ac: No transient candidates in CALET observations
  31. LIGO/Virgo S200219ac: no counterpart candidates in the Swift/BAT observations
  32. Fermi trigger No 603849435: Global MASTER-Net observations report
  33. LIGO/Virgo S200219ac: No counterpart candidates in Fermi-LAT observations
  34. LIGO/Virgo S200219ac: upper limits from AGILE/GRID observations
  35. LIGO/Virgo S200213t: Keck/LRIS spectroscopy of counterpart candidates from the Zwicky Transient Facility
  36. LIGO/Virgo S200219ac: upper limits from AGILE/MCAL observations
  37. LIGO/Virgo S200219ac: No counterpart candidates in HAWC observations
  38. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  39. LIGO/Virgo S200219ac: Global MASTER-Net observations report
  40. Swift GRB200219.32: Global MASTER-Net observations report
  41. LIGO/Virgo (S200213t/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
  42. LIGO/Virgo S200213t: No EM counterparts found from continued GECKO observation of host galaxy candidates
  43. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  44. Further Swift-XRT observations of Swift J0840.7-3516
  45. GRB 200216B - possible IR counterpart from VLT
  46. GRB 200216B: z-band limit from NOT
  47. GRB 200216B: Swift/UVOT Upper Limits
  48. GRB 200215A: RATIR Optical Observations
  49. GRB 200216B: Nanshan/NEXT early optical upper limit and possible host galaxy
  50. Swift GRB200216.56: Global MASTER-Net observations report
  51. GRB 200215A: UKIRT H-band observations
  52. LIGO/Virgo S200213t: Updated coverage and candidate list for the Zwicky Transient Facility
  53. LIGO/Virgo S200213t: CLU/NED Galaxies in the 4-Update Localization Volume
  54. GRB 200215A: Swift/UVOT Upper Limits
  55. GRB 200215A: Optical observations form Calar Alto 2.2m
  56. LIGO/Virgo S200213t: No transient candidates in CALET observations
  57. LIGO/Virgo S200213t: Lulin Follow-Up Observations
  58. GRB 200215A: Nanshan/NEXT optical upper limit
  59. Swift GRB200215.61: Global MASTER-Net observations report
  60. LIGO/Virgo S200213t: MASTER possible Kilonova candidate in PGC315337
  61. LIGO/Virgo S200213t: P200 Spectroscopy of ZTF20aanakcd/AT2020cmr
  62. LIGO/Virgo S200213t: DBSP spectroscopy of AT2020cjb/ZTF20aamvnth, AT2020cja/ZTF20aamvmzj, AT2020cjc/ZTF20aamvoeh
  63. LIGO/Virgo S200114f: Gemini Spectra of AT 2020vu, AT 2020vw, AT 2020vy, and AT 2020vz
  64. LIGO/Virgo S200213t: MASTER OT detection in PGC673735
  65. LIGO/Virgo S200213t: Upper limits from Insight-HXMT/HE observations
  66. LIGO/Virgo S200213t: No counterpart candidates from Nanshan-0.6m observations
  67. LIGO/Virgo S200213t: No notable candidates in GOTO imaging
  68. LIGO/Virgo S200213t: One additional candidate from the Zwicky Transient Facility
  69. LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
  70. LIGO/Virgo S200213t: More Candidates from the Zwicky Transient Facility
  71. LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
  72. LIGO/Virgo S200213t: No counterpart candidates in Fermi-LAT observations
  73. LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
  74. LIGO/Virgo S200213t: MANGROVE catalog galaxy ranking
  75. LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations
  76. LIGO/Virgo S200213t: upper limits from AGILE/GRID observations
  77. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  78. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  79. LIGO/VIRGO S200213t: upper limits from AGILE/MCAL observations
  80. LIGO/Virgo S200213t: Candidates from the Zwicky Transient Facility
  81. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  82. LIGO/Virgo S200213t: NED Galaxies in the 90% Localization Volume
  83. LIGO/Virgo S200213t: Global MASTER-Net observations report
  84. ZTF20aajnksq: Upper limits from Konus-Wind observations
  85. Fermi trigger No 603197394: Global MASTER-Net observations report
  86. GRB 200131A: Tautenburg observations
  87. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  88. LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
  89. GRB 200205B: Chilescope optical observations
  90. LIGO/Virgo S200129m: Upper limits from Insight-HXMT/HE observations
  91. LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
  92. LIGO/Virgo S200208q: no counterpart candidates in the Swift/BAT observations
  93. LIGO/Virgo S200208q: Upper limits from Fermi-GBM Observations
  94. LIGO/Virgo S200208q : upper limits from AGILE/GRID observations
  95. LIGO/Virgo S200208q: upper limits from AGILE/MCAL observations
  96. LIGO/Virgo S200208q: Global MASTER-Net observations report
  97. LIGO/Virgo S200208q: No counterpart candidates in HAWC observations
  98. Fermi trigger No 602817262: Global MASTER-Net observations report
  99. Fermi trigger No 602731380: Global MASTER-Net observations report
  100. Swift GRB200207.13: Global MASTER-Net observations report

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