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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"

27859 results found.

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

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