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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').
Advanced Search

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"

39257 results found.

  1. GRB 260421B: SVOM/VT optical observations
  2. GRB 260310A: Late-time Chandra X-ray Detection
  3. GRB 260418A: Insight-HXMT/HE detection
  4. EP260416a: 1.3m DFOT optical observation
  5. GRB 260415A: CALET Gamma-Ray Burst Monitor detection
  6. GRB 260415B: CALET Gamma-Ray Burst Monitor detection
  7. Fermi GRB 260421C: Global MASTER-Net observations report
  8. GRB 260421C: Fermi GBM Final Real-time Localization
  9. GRB 260421B: VLT/X-shooter spectroscopic redshift z = 2.115
  10. Fermi GRB 260421B: Global MASTER-Net observations report
  11. GRB 260421B: BOOTES-7 early optical afterglow detection
  12. GRB 260421B: LCO optical afterglow confirmation
  13. GRB 260421B: SVOM/COLIBRÍ (FM-GFT) optical detection of a candidate counterpart
  14. GRB 260421B: TRT optical counterpart detection
  15. GRB 260421B: SVOM detection of a long burst
  16. GRB 260421B: BALROG localization (Fermi Trigger 798437606 / GRB 260421176)
  17. GRB 260421B: Fermi GBM Final Real-time Localization
  18. Fermi GRB 260421A: Global MASTER-Net observations report
  19. GRB 260421A: Fermi GBM Final Real-time Localization
  20. GRB 260412A: LCOGT Optical Upper Limits
  21. GOTO26djh/AT2026jpw: CrAO and Mondy optical observations of the transient
  22. EP-WXT trigger 01709260303: KAIT optical observations
  23. GRB 260417A: SVOM/GRM observation
  24. EP260321A/AT2026gzf: Optical observation from 1.3m DFOT
  25. GRB 260419B: Fermi GBM Final Real-time Localization
  26. GRB 260419A: Fermi GBM Final Real-time Localization
  27. Fermi trigger No 798275385: Global MASTER-Net observations report
  28. EP260417a: GROWTH-India Telescope optical upper limit
  29. Fermi GRB 260417B: Global MASTER-Net observations report
  30. EP260417b: GROWTH-India Telescope optical upper limit
  31. GRB 260418B: Fermi GBM Final Real-time Localization
  32. EP260416a: VLT/FORS2 spectroscopic redshift confirmation
  33. EP260417a: Global MASTER-Net observations report
  34. EP260417a/GRB 260417A: refined analysis of the EP-WXT and follow-up EP-FXT observations
  35. GRB 260418A: Fermi GBM Final Real-time Localization
  36. Fermi GRB 260417A: Global MASTER-Net observations report
  37. Konus-Wind detection of GRB 260411B
  38. GRB 260417B: Fermi GBM Final Real-time Localization
  39. GRB 260417A: AstroSat CZTI detection
  40. IPN triangulation of GRB 260411B
  41. EP260416a: LCO observations confirm end of flaring phase
  42. EP260417a: TRT optical counterpart detection
  43. EP-WXT trigger 01709259586: KAIT optical observations
  44. EP260416a: KAIT optical upper limit
  45. GRB 260414A: Insight-HXMT/HE detection
  46. EP260416a: COLIBRÍ confirmation of the optical rebrightening
  47. GRB 260417A: Fermi GBM Final Real-time Localization
  48. GOTO26djh/AT2026jpw: ZTSh R,I bands observations of the transient
  49. GRB 260415B: Glowbug gamma-ray detection
  50. GRB 260411B: Glowbug gamma-ray detection
  51. GRB 260415A: Insight-HXMT/HE detection
  52. EP260416a: COLIBRÍ optical counterpart candidate
  53. COLIBRI optical observations of the transient GOTO26djh/AT2026jpw
  54. EP260416a: Global MASTER-Net observations report
  55. GOTO26djh/AT2026jpw: EP-FXT X-ray counterpart detection
  56. GOTO26djh/AT2026jpw transient: SAO RAS optical observations
  57. GRB 260415B: NuSTAR detection of long prompt emission
  58. GOTO discovery of fast-fading transient GOTO26djh/AT2026jpw, a candidate orphan afterglow
  59. GRB 260415B: Fermi GBM Final Localization
  60. GRB 260415A: Fermi GBM Final Real-time Localization
  61. Fermi trigger No 797912738: Global MASTER-Net observations report
  62. GRB 260414A: Glowbug gamma-ray detection
  63. EP260321a: CMO SAI J,K observations
  64. GRB 260412A: Insight-HXMT/HE detection
  65. GRB 260414A: Fermi GBM Final Real-time Localization
  66. Fermi GRB 260413A: Global MASTER-Net observations report
  67. GRB 260410A: Glowbug gamma-ray detection of a short burst
  68. GRB 260413A: Fermi GBM Final Real-time Localization
  69. GRB 260410B: Insight-HXMT/HE detection
  70. GRB 260410A: Insight-HXMT/HE detection
  71. Konus-Wind detection of GRB 260410A (short/hard)
  72. GRB 260411B: GECAM-B observation of a long burst
  73. GRB 260410A: CALET Gamma-Ray Burst Monitor detection
  74. GRB 260412A: GECAM-B observation of a long burst
  75. Fermi GRB 260412A: Global MASTER-Net observations report
  76. GRB 260412A: Fermi GBM Observation
  77. GRB 260310A / AT2026fgk: NuSTAR detection of the rebrightening
  78. GRB 260411B: Fermi-LAT detection
  79. GRB 260412A: SVOM detection of a long burst
  80. GRB 260412A: Fermi GBM Final Real-time Localization
  81. GRB 260411B: COLIBRÍ optical observations
  82. GRB 260410B: Fermi GBM Observation
  83. GRB 260411B: Ondrejov D50 optical afterglow detection
  84. GRB260411B: 3.6m DOT optical observation
  85. GRB 260411A: SVOM/GRM observation
  86. GRB 260407B: SVOM/GRM detection of a possible magnetar X-ray burst
  87. GRB 260411B: SVOM/GRM observation of a long burst
  88. GRB 260409A: Insight-HXMT/HE detection
  89. GRB 260411B: Fermi GBM Detection
  90. GRB 260411B: GOTO optical counterpart candidate
  91. GRB 260411B: BALROG localization (Fermi Trigger 797587480 / GRB 260411337)
  92. GRB 260411B: Fermi GBM Final Real-time Localization
  93. GRB 260411A: Fermi GBM Final Real-time Localization
  94. GRB 260410A: COLIBRÍ optical upper limit
  95. GRB 260410A: Fermi GBM Observation
  96. GRB 260410B: SVOM/GRM detection of a short faint burst
  97. GRB 260410B: Fermi GBM Final Real-time Localization
  98. GRB 260410A: Fermi-LAT detection
  99. GRB 260410A: Fermi GBM Final Real-time Localization
  100. EP260321a: Chandra X-ray Non-detection

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