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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

27854 results found.

  1. SVOM GRB260903.53: Global MASTER-Net observations report
  2. GRB 260903A: LCO optical counterpart detection
  3. GRB 260827A: Insight-HXMT/HE detection
  4. EP260901a: SVOM/VT optical upper limits
  5. EP260901a: EP-FXT follow-up observation
  6. GRB 260829A: SVOM/GRM observation
  7. GRB 260818A: ATCA detection of a candidate radio counterpart
  8. EP260830a: EP-FXT follow-up observation
  9. EP260901a: Global MASTER-Net observations report
  10. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  11. NuSTAR Transient 260828: LCO Optical Upper Limits
  12. EP260901a: EP-WXT detection of a fast X-ray transient
  13. GRB 260830A: NuSTAR detection of prompt emission
  14. GRB 260831B: LCO optical upper limits
  15. EP260830a: Global MASTER-Net observations report
  16. EP260830a: EP-WXT detection of a fast X-ray transient
  17. GRB 260827A: SVOM/GRM observation
  18. NuSTAR 260828: a 1100s hard X-ray transient
  19. GRB 260831B: SVOM detection of a possible burst
  20. GRB 260827A: Glowbug gamma-ray detection
  21. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  22. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  23. GRB 260825A: SVOM/GRM observation of a long burst
  24. GRB 260829A: Fermi GBM Detection
  25. GRB 260825A: AstroSat CZTI detection
  26. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  27. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  28. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  29. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  30. GRB 260818B: Further EP-FXT observation
  31. GRB 260818B: VLT optical and nIR observations
  32. GRB 260818B: TNG NIR observations
  33. MAXI GRB260827.40: Global MASTER-Net observations report
  34. GRB 260818B: 6 GHz VLA observations
  35. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  36. GRB 260808B: SAO RAS observations of the optical rebrightening
  37. EP260822a: Global MASTER-Net observations report
  38. EP Alert 260820.31: Global MASTER-Net observations report
  39. GRB 260807A: EP-FXT follow-up observations
  40. IceCube Alert 260825A: Global MASTER-Net observations report
  41. IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
  42. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  43. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  44. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  45. EP260822a: EP-FXT non-detection and upper limit
  46. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  47. EP260822a: Einstein Probe detection of a fast X-ray transient
  48. GRB 260822A: LCO optical upper limits
  49. GRB 260822A: GROWTH-India Telescope Upper Limits
  50. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  51. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  52. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  53. GRB 260818B: VLA radio observations
  54. GRB 260818B: SVOM/C-GFT optical upper limit
  55. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  56. IceCube Alert 260821A: Global MASTER-Net observations report
  57. GRB 260820A: Insight-HXMT/HE detection
  58. EP detected a brightening of LMXB 1ES 1735-26.9
  59. GRB 260818A: J-band observations with WINTER
  60. GRB 260818A: SVOM/ECLAIRs refined analysis
  61. GRB 260818B: NOT optical upper limits
  62. GRB 260810A: SVOM/GRM observation
  63. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  64. GRB 260818B: LCO optical upper limits
  65. GRB 260818B: SVOM detection of a short burst
  66. EP260806a: SAO RAS multicolor optical observations
  67. GRB 260818A: LCO optical upper limits
  68. EP260812a: AbAO optical upper limit
  69. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  70. GRB 260810A: Insight-HXMT/HE detection
  71. GRB 260818A: SVOM possible detection of a long and faint GRB
  72. EP260806a: NUTTELA-TAO optical observations
  73. The EP-WXT trigger 01709281429 is likely a flaring star
  74. EP260812a: AZT-22 optical upper limit
  75. EP260806a: WFST optical observations
  76. EP260812b: Optical upper limit with Kinder
  77. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  78. GRB 260808B: Liverpool Telescope further optical observations
  79. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  80. EP260812a: NOT and Liverpool Telescope upper limits:
  81. EP260812b: Liverpool Telescope observations
  82. EP260812b: GOTO detection of the optical counterpart
  83. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  84. EP260812a: SVOM/C-GFT optical upper limit
  85. EP260812b: COLIBRÍ optical observations
  86. EP260812b: SVOM/VT optical observation
  87. GRB 260808A: SVOM/GRM observation
  88. EP260812b: Einstein Probe detection of an X-ray transient
  89. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  90. Fermi GBM Sub-Threshold Detection of GRB 260809A
  91. GRB 260810A: Glowbug gamma-ray detection
  92. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  93. GRB 260810A: AstroSat CZTI detection of a long burst
  94. EP260812a: Einstein Probe detection of an X-ray transient
  95. GRB 260809A: SAO RAS optical observations
  96. GRB 260808B: SAO RAS optical observations
  97. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  98. EP260806a: MAO/AZT-22 optical observations
  99. IceCube-260807A: Upper limits from a search for additional neutrino events in IceCube
  100. GRB260808B: MAO/AZT-22 optical observations

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