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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"

32762 results found.

  1. GRB 250919A/EP250919A: Swift/UVOT afterglow detection
  2. GRB 250919A: Swift-XRT afterglow detection
  3. GRB 250919A: Fermi-LAT detection
  4. EP250919a/GRB 250919A: Gemini/GMOS-S spectroscopic redshift z = 1.145
  5. GRB 250919A: SVOM/GRM observation of a very bright GRB
  6. EP250919a: Global MASTER-Net observations report
  7. EP250919a: Einstein Probe detection of an X-ray transient
  8. Correction for GCN 41877: EP-WXT ID is 01709243841
  9. GRB 250916A: Fermi GBM Observation
  10. Fermi GRB 250919A: Global MASTER-Net observations report
  11. GRB 250916A: KAIT optical observations
  12. GRB 250917B: VLT/HAWK-I near-infrared observations
  13. GRB 250916A: NuSTAR detection of the prompt emission
  14. GRB 250916A: further SAO RAS optical observations
  15. GRB 250912A: SVOM/ECLAIRs refined analysis
  16. GRB 250917B: Swift-BAT refined analysis
  17. GRB 250917B: Swift/UVOT Upper Limits
  18. GRB 250916A: OSIRIS+/GTC redshift z = 2.015
  19. GRB 250916A: Swift-XRT observations
  20. EP250916a: EP-FXT follow-up observation
  21. GRB 250916A: MAO/AZT-22 optical observations
  22. GRB 250916A: SAO RAS optical observations
  23. GRB 250916A : GIT optical observations
  24. LIGO/Virgo/KAGRA S250917aq: Updated Sky localization
  25. GRB 250916A: Glowbug gamma-ray detection
  26. GRB250917B: WFST optical observations
  27. GRB 250916A: Swift ToO observations
  28. GRB 250917B: Fermi GBM Observation
  29. LIGO/Virgo/KAGRA S250917aq: Identification of a GW compact binary merger candidate
  30. Fermi GRB 250917B: Global MASTER-Net observations report
  31. GRB 250916A: GOTO optical counterpart candidate
  32. GRB 250916A: AstroSat CZTI detection of a bright long burst
  33. GRB 250910A: SVOM/ECLAIRs refined analysis
  34. Fermi GRB 250916A: Global MASTER-Net observations report
  35. EP250827b: VLA Observations
  36. LIGO/Virgo/KAGRA S250818k: HCT optical follow-up
  37. SVOM/sb25091517: Confirmation of a stellar flare by SVOM/VT
  38. SVOM/sb25091517: FRAM-ORM stellar flare - transient observation
  39. GRB 250912A: Swift/BAT-GUANO localization skymap of a possibly short burst
  40. GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
  41. GRB 250912A: Swift-XRT observations
  42. GRB250912A: VLT/HAWK-I follow-up observations
  43. GRB 250912A: VLT observations
  44. GRB 250912A: Fermi GBM Observation
  45. GRB 250911A: Insight-HXMT detection
  46. GRB 250912A: SVOM/GRM analysis suggests a possible short GRB with extended emission
  47. GRB 250912A:SVOM/VT optical upper limit
  48. GRB 250912A: LCO optical upper limit
  49. Fermi GRB 250912A: Global MASTER-Net observations report
  50. EP250911a: Global MASTER-Net observations report
  51. GRB 250912A: SVOM detection of a burst
  52. EP250908c: tentative VLT/FORS2 redshift z = 2.87
  53. EP250911a: Upper limit from Fermi-GBM Observations
  54. LIGO/Virgo/KAGRA S250912f: Updated Sky localization
  55. GRB 250911A: GECAM-B detection
  56. GRB 250911A: Swift-BAT refined analysis
  57. EP250911a: GTC/OSIRIS+ spectroscopic redshift z = 3.84
  58. LIGO/Virgo/KAGRA S250912f: Identification of a GW compact binary merger candidate
  59. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  60. GRB 250910B: SVOM/GRM observation
  61. EP250911a: SVOM/VT optical observation
  62. GRB 250911A: MASTER optical counterpart observations
  63. EP250911a: SAO RAS optical observations
  64. EP250911a: Swift-XRT observations
  65. EP250911a: Optical detection with Kinder observations
  66. GRB 250911A: Swift/UVOT Detection
  67. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  68. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  69. GRB 250909B: Insight-HXMT detection
  70. GRB 250909B: SVOM/GRM observation
  71. LIGO/Virgo/KAGRA S250911ac: Updated Sky localization and Source Classification
  72. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  73. EP250911a: COLIBRÍ optical observations
  74. LIGO/Virgo/KAGRA S250908y: Updated Sky localization
  75. Fermi GRB 250910B: Global MASTER-Net observations report
  76. EP250911a: LCO optical counterpart discovery
  77. EP250910a: Global MASTER-Net observations report
  78. GRB 250404A / EP250404a: spectroscopic redshift at z = 1.88 (correction to GCN 40084)
  79. LIGO/Virgo/KAGRA S250911ac: Identification of a GW compact binary merger candidate
  80. GRB 250903A: SVOM/ECLAIRs refined analysis
  81. GRB 250911A: COLIBRÍ optical counterpart candidate
  82. LIGO/Virgo/KAGRA S250906ca: Updated Sky localization
  83. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  84. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  85. GRB 250910A: SVOM/VT optical upper limit
  86. EP250908C: GROND observation of the fading optical counterpart
  87. GRB 250910A: LCO optical upper limit
  88. GRB 250909A: AstroSat CZTI detection
  89. GRB 250910A: SVOM/MXT possible afterglow detection
  90. GRB 250702B: Late time Chandra observations
  91. EP250908b/EP#01709240653: Swift/UVOT Detection
  92. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  93. GRB 250907A: CALET Gamma-Ray Burst Monitor detection
  94. EP250908c: SVOM/VT optical observation
  95. EP250908c: VLT/FORS2 optical counterpart identification
  96. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  97. EP250908b: SVOM/VT optical candidate
  98. EP250908c: Global MASTER-Net observations report
  99. Fermi GRB 250909A: Global MASTER-Net observations report
  100. LIGO/Virgo/KAGRA S250908y: Identification of a GW compact binary merger candidate

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