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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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

28221 results found.

  1. EP251124a: Pan-STARRS ri-band imaging and photometry
  2. GRB 251126A: Mondy and SAO RAS optical observations
  3. GRB 251126A: Swift-XRT refined Analysis
  4. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  5. GRB 251126A: NOT optical observations
  6. GRB 251126A: 1.3m DFOT optical afterglow detection
  7. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  8. GRB 251125B: GECAM-B detection
  9. GRB 251127A: Fermi GBM Final Real-time Localization
  10. GRB 251126A: Enhanced Swift-XRT position
  11. GRB 251126A: Kilonova-Catcher optical afterglow detection
  12. GRB 251126A: Asiago i-band detection
  13. GRB 251126A: Nanshan/HMT optical afterglow detection
  14. GRB 251126A: Prompt enhanced Swift-XRT position
  15. GRB 251126A: GIT discovery of the likely optical afterglow
  16. GRB 251126A: Swift detection of a burst
  17. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  18. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  19. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  20. GRB 251125B: Fermi GBM Final Real-time Localization
  21. EP251124b: EP-WXT detection of a fast X-ray transient
  22. EP251124a: Xinglong GWAC-F60A optical observation
  23. GRB 251125A: Fermi GBM Final Real-time Localization
  24. EP251124a: NOT r- and z-band optical upper limits
  25. EP251124a: Swift-XRT observations
  26. GRB 251124A: Fermi GBM Localization by automated pipeline
  27. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  28. GRB 251122B: Fermi GBM Final Localization
  29. EP251118A: 6 GHz VLA Detection
  30. GRB 251124a: Fermi GBM Final Localization
  31. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  32. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  33. EP251124a: Einstein Probe detection of an X-ray transient
  34. GRB 251116C: Swift-XRT confirmation of fading
  35. GRB 251122A/EP251122A: 1.3m DFOT optical detection
  36. EP251118A: 3.6m DOT optical afterglow detection
  37. GRB 251122A / EP251122a: EP-FXT counterpart detection
  38. GRB 251122A / EP251122a: WFST optical observations
  39. GRB 251122A/EP251122a: SVOM/VT optical observations with VHF data
  40. GRB 251122A/EP251122a: Additional, deeper LCO optical r band upper limit
  41. EP251122a / GRB 251122A: optical counterpart candidate with Kinder observations
  42. GRB 251122A / EP251122a: SVOM detection of a long burst
  43. EP251122a: Einstein Probe detection of an X-ray transient
  44. EP251118a: Continued Optical Detection with Kinder observations
  45. LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
  46. GRB 251121A: Glowbug gamma-ray detection of a likely short burst
  47. EP251118a: Xinglong-2.16m optical observation
  48. GRB 251121A: Fermi GBM Final Real-time Localization
  49. EP251118A: 1.3m DFOT optical afterglow detection
  50. GRB 251118A: Swift/UVOT Detection
  51. GRB 251118A: Glowbug gamma-ray detection
  52. GRB 251118A: Fermi GBM Observation
  53. GRB 251118A: Swift-XRT afterglow detection
  54. GRB 251103A: SVOM/ECLAIRs and SVOM/GRM joint refined analysis
  55. EP251118a: Optical detection with Kinder observations
  56. GRB 251118A: GECAM-B detection
  57. GRB 251118A: NuSTAR detection of bright prompt emission
  58. EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
  59. GRB 251116C: NOT optical observations
  60. GRB 251118C: Glowbug gamma-ray detection of the fast X-ray transient EP251118A
  61. GRB 251118C: Swift/BAT rates detection of a burst with a possible association with EP 251118A
  62. GRB 251018A: FRAM-Auger optical detection
  63. GRB 251117A: Swift-XRT observations
  64. Konus-Wind detection of GRB 251118C (EP251118a)
  65. GRB 251117A: Insight-HXMT/HE detection
  66. EP251118a: GOTO optical afterglow detection
  67. GRB 251119A: SVOM detection of a possible burst
  68. EP251118a: NOT spectroscopic redshift of z = 1.216
  69. GRB 251118A: Fermi-LAT detection
  70. EP251118a: NOT candidate optical counterpart
  71. GRB 251118A: Swift ToO observations
  72. EP251118a: Einstein Probe detected of a fast X-ray transient
  73. GRB 251118B: Fermi GBM Final Real-time Localization
  74. GRB 251118A: Fermi GBM Final Real-time Localization
  75. GRB 251117A: AstroSat CZTI detection
  76. GRB 251114B: Insight-HXMT/HE detection
  77. GRB 251114B: GECAM-B detection of a short burst
  78. GRB 251013C: Koshka, SAO RAS, Mondy, and CrAO optical observations, possible SN detection
  79. GRB 251116D: Insight-HXMT/HE detection
  80. GRB 251115A: Swift-XRT observations
  81. GRB 251117A: Tiled Swift observations
  82. GRB 251117A: Fermi-LAT detection
  83. GRB 251116C: Swift/BAT arcminute localization of a burst
  84. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  85. GRB 251116C: Swift-XRT observations
  86. GRB 251117A: Fermi GBM Final Localization Correction
  87. GRB 251116D: Glowbug gamma-ray detection
  88. GRB 251116D: AstroSat CZTI detection
  89. GRB 251116C: SVOM/VT optical upper limit
  90. GRB 251116C: SVOM detection of a burst
  91. GRB 251116B: SVOM detection of a burst
  92. GRB 251116A: Fermi GBM Final Real-time Localization
  93. GRB 251115A: Tiled Swift observations
  94. GRB 251115A: Fermi-LAT detection
  95. GRB 251115A: Fermi GBM Final Real-time Localization
  96. GRB 251113A: Glowbug gamma-ray detection
  97. GRB 251113A: AstroSat CZTI detection
  98. GRB 251114B: Fermi GBM Final Real-time Localization
  99. Konus-Wind detection of GRB 251108C
  100. Konus-Wind detection of GRB 251103A

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