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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"

15373 results found.

  1. GRB 251005C: Fermi GBM Observation
  2. GRB 251002A: Insight-HXMT detection
  3. GRB 251002A: Insight-HXMT detection
  4. GRB 251002A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  5. GRB 251003A: Swift/UVOT Upper Limits
  6. GRB 251002A: Swift/UVOT detection
  7. GRB 251001A: AstroSat CZTI detection
  8. GRB 251001B: COLIBRÍ further observations and evidence of a multi-wavelength shallow decay
  9. GRB 251002A: Fermi GBM Observation
  10. GRB 251001C: SVOM/GRM observation
  11. GRB 251003A: Kilonova-Catcher optical afterglow detection
  12. GRB 251002A: Kilonova-Catcher optical afterglow detection
  13. GRB 251002A: SVOM/COLIBRÍ (FM-GFT) optical observations
  14. GRB 251002A: OHP/T193 MISTRAL optical afterglow detection
  15. GRB 251002A: EP-FXT counterpart detection
  16. GRB 251003A: COLIBRÍ optical detection of the fading afterglow
  17. GRB 251002A: BOOTES-6 early optical detection
  18. GRB 251002A: FRAM-ORM afterglow detection
  19. GRB 251002A: LCO optical observation
  20. GRB 251002A: SVOM detection of a burst
  21. GRB 251001A: SVOM/GRM observation
  22. GRB 251001A: Insight-HXMT detection
  23. GRB 251001B: COLIBRÍ optical observations
  24. GRB 251001B: GTC/OSIRIS+ spectroscopic redshift z = 2.162
  25. GRB 251001B: Fermi GBM Observation
  26. GRB 250930A: SVOM/GRM observation
  27. GRB 251001A: Fermi GBM Detection
  28. GRB 250910A / EP250910a: VLT limits on the possible associated supernova
  29. LIGO/Virgo/KAGRA S250830bp: SOAR spectroscopy of two DESGW candidates
  30. LIGO/Virgo/KAGRA S250818k: further MeerKAT monitoring
  31. Fermi-LAT Gamma-ray Observations of IceCube-250926A
  32. GRB 250924A: SVOM/GRM observation
  33. IceCube-250926A: Upper limits from a search for additional neutrino events in IceCube
  34. GRB 250926A: Insight-HXMT detection
  35. GRB 250920C: ULL-ASTRO-MASTER early detection of the optical afterglow with LCO 40-cm telescope at Siding Spring Observatory
  36. GRB 250926A: AstroSat CZTI detection
  37. GRB 250925A: Swift/UVOT Upper Limits
  38. IceCube-250926A - IceCube observation of a high-energy neutrino candidate track-like event
  39. GRB 250925A/EP250925a: EP-WXT detection
  40. GRB 250926A: DDOTI Optical Observations and Spatial Coincidence with the Orion Nebula
  41. GRB 250925A : MITSuME Akeno optical upper limits
  42. GRB 250925A: JinShan optical observations
  43. GRB 250925A: 1.5m OSN optical detection and redshift with the 10.4m GTC/OSIRIS+
  44. GRB 250925A: COLIBRÍ optical photometry of the afterglow
  45. GRB 250922A: SVOM/GRM observation
  46. GRB 250924A: 1.6m Mephisto optical upper limits
  47. GRB 250924A: AstroSat CZTI detection
  48. GRB 250914A: AstroSat CZTI detection
  49. GRB 250920B: AstroSat CZTI detection
  50. GRB 250924A: KAIT optical observations
  51. GRB 250924A: Kilonova-Catcher optical afterglow detection
  52. GRB 250920C: Kilonova-Catcher optical afterglow detection
  53. GRB 250922B: SVOM/GRM observation
  54. GRB 250924A: COLIBRÍ optical observations
  55. Konus-Wind detection of GRB 250920C
  56. EP250911a: e-MERLIN radio observations
  57. GRB 250920C: SALT redshift confirmation
  58. GRB 250920C: COLIBRÍ optical observations
  59. GRB 250922C: AstroSat CZTI detection of a short burst
  60. GRB 250920C: PRIME near-infrared detection
  61. Konus-Wind detection of GRB 250920B
  62. Konus-Wind detection of GRB 250920A
  63. Konus-Wind detection of GRB 250911A
  64. GRB 250920C: SVOM/GRM observation
  65. GRB 250920C: GTC/OSIRIS+ spectroscopic redshift z = 1.40
  66. GRB 250920C: GROWTH-India Telescope optical observations
  67. GRB 250920C: Optical counterpart detection by LCO
  68. GRB 250920A: SVOM/GRM observation
  69. GRB 250920B: SVOM/C-GFT optical observations
  70. Konus-Wind detection of GRB 250919A
  71. LIGO/Virgo/KAGRA S250920bq: Coverage and upper limits from MAXI/GSC observations
  72. GRB 250919A / EP250919a: Insight-HXMT detection
  73. GRB 250920A: AstroSat CZTI detection
  74. GRB 250918A: SVOM/GRM observation
  75. GRB 250919A/EP250919A: Swift/UVOT afterglow detection
  76. GRB 250919A: Fermi-LAT detection
  77. GRB 250919A: SVOM/GRM observation of a very bright GRB
  78. GRB 250916A: Fermi GBM Observation
  79. GRB 250917B: VLT/HAWK-I near-infrared observations
  80. GRB 250912A: SVOM/ECLAIRs refined analysis
  81. GRB 250916A : GIT optical observations
  82. LIGO/Virgo/KAGRA S250917aq: Three counterpart neutrino candidates from IceCube neutrino searches
  83. GRB 250916A: Glowbug gamma-ray detection
  84. GRB 250916A: Swift ToO observations
  85. GRB 250917B: Fermi GBM Observation
  86. GRB 250916A: AstroSat CZTI detection of a bright long burst
  87. GRB 250910A: SVOM/ECLAIRs refined analysis
  88. LIGO/Virgo/KAGRA S250818k: HCT optical follow-up
  89. SVOM/sb25091517: Confirmation of a stellar flare by SVOM/VT
  90. SVOM/sb25091517: FRAM-ORM stellar flare - transient observation
  91. SVOM/sb25091517: SVOM detection of an X-ray transient
  92. GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
  93. GRB 250912A: Swift-XRT observations
  94. GRB250912A: VLT/HAWK-I follow-up observations
  95. GRB 250912A: Fermi GBM Observation
  96. GRB 250911A: Insight-HXMT detection
  97. GRB 250912A: SVOM/GRM analysis suggests a possible short GRB with extended emission
  98. GRB 250912A: SVOM detection of a burst
  99. IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
  100. EP250911a: Upper limit from Fermi-GBM Observations

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