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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"

23687 results found.

  1. GRB 251014B: PRIME J-band upper limit
  2. GRB 251013C: Kilonova-Catcher optical afterglow detection
  3. GRB 251013D: Swift/UVOT Observations
  4. GRB 251013C: Swift/UVOT Detection
  5. Konus-Wind detection of GRB 251007A
  6. GRB 251013C: SVOM/ECLAIRs refined analysis
  7. Swift Trigger 1404295: possible GRB 251015A
  8. GRB 251014D: BOOTES-6/DPRT optical upper limit
  9. GRB 251013C: MAO/AZT-22 optical observations
  10. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) further multi-band optical observations
  11. GRB 251014A: Swift-BAT refined analysis
  12. GRB 251013C: OHP/T193 further optical observations and possible color evolution
  13. GRB 251014D: Swift detection of a burst
  14. GRB 251014A: PRIME near-infrared upper limits
  15. GRB 251014A: Glowbug gamma-ray detection of a likely short burst
  16. GRB 251012A: Glowbug gamma-ray detection of a likely short burst
  17. GRB 251013D: LAST optical upper limit on Swift/BAT-GUANO localization
  18. GRB 251013C: Early and late-time optical counterpart detection by LCO
  19. LIGO/Virgo/KAGRA S251014cn: NED Galaxies in the 3-Initial Localization Volume
  20. GRB 251014A: DDOTI Upper Limit
  21. GRB 251013C NUTTelA-TAO / BSTI Early Measurements
  22. LIGO/Virgo/KAGRA S251014cn: Identification of a GW compact binary merger candidate
  23. GRB 251013C: ULL-ASTRO-MASTER detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  24. GRB 251013A: CALET Gamma-Ray Burst Monitor detection
  25. GRB 251013C: ABObservatory optical observations
  26. GRB 251014A: SAO RAS optical upper limit
  27. GRB 251014A: Fermi GBM Observation
  28. GRB 251013C: J band observations by SYSU 80cm infrared telescope
  29. GRB 251013C: AstroSat CZTI detection
  30. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) detection of the optical counterpart
  31. GRB 251013C: DDOTI detection of the optical afterglow
  32. GRB 251014A: Swift detection of a possibly-short burst
  33. Fermi trigger No 782044789: Global MASTER-Net observations report
  34. GRB 251013C: Swift-XRT counterpart detection
  35. GRB 251013C: GOTO optical afterglow detection
  36. GRB 251013C: SAO RAS optical observations
  37. GRB 251013C: LCO optical afterglow detection
  38. GRB 251013C: LAST detection of optical counterpart
  39. GRB 251013C: BOOTES-6 early optical detection
  40. GRB 251013C: SVOM/VT optical observation
  41. LIGO/Virgo/KAGRA S251013x: Identification of a GW compact binary merger candidate
  42. GRB 251011B inspection: MASTER orphan GRB detection
  43. GRB 251011A: Insight-HXMT detection
  44. GRB 251011B: Swift/UVOT Upper Limits
  45. GRB 251011B: Swift-XRT refined Analysis
  46. GRB 251010A: AstroSat CZTI detection
  47. GRB 251011A: AstroSat CZTI detection
  48. GRB 251011B: Swift detection of a burst
  49. GRB 251007B: Swift/UVOT Upper Limits
  50. GRB251007A: Swift/UVOT Detection
  51. GRB 251009B (short): Glowbug gamma-ray detection
  52. GRB 251007A: Swift-BAT refined analysis
  53. GRB 251006A: CALET Gamma-Ray Burst Monitor detection
  54. GRB 251007B - SVOM/ECLAIRs refined analysis
  55. GRB 250916A: TERI Gamma-ray detection
  56. GRB 250919A: TERI gamma-ray detection
  57. GRB 251006A: Fermi GBM Observation
  58. GRB 251007A: 1.5m OSN and 2.2m CAHA optical follow-up
  59. GRB 251002A - SVOM/ECLAIRs refined analysis
  60. GRB 251007B: COLIBRÍ optical upper limit
  61. GRB 251007A: AstroSat CZTI detection
  62. GRB 251006B/EP251006a: EP-FXT afterglow detection
  63. GRB 250917B: iTelescope T-26 upper limit
  64. GRB 251007B: SVOM/VT optical candidate
  65. GRB 251007B: Swift-XRT refined Analysis
  66. GRB 251007A: CALET Gamma-Ray Burst Monitor detection
  67. GRB 251005C: PRIME J-band upper limit
  68. GRB 251007A: Glowbug gamma-ray detection
  69. GRB 251007B: SVOM/C-GFT upper limit
  70. GRB 251007B: Swift detection of a burst
  71. GRB 251007A: Swift detection of a burst with an optical counterpart
  72. GRB 250702B/EP250702a: JWST/NIRCam Observations
  73. GRB 251005B: Glowbug gamma-ray detection
  74. EP251003a: LCO and VST fading optical counterpart
  75. GRB 251006B/EP251006a: EP-FXT follow-up observation
  76. GRB 251006B: COLIBRÍ optical upper limit
  77. GRB 251006B/EP251006a: EP-WXT detection
  78. LIGO/Virgo/KAGRA S251006dd: Identification of a GW compact binary merger candidate
  79. GRB 251006B: Fermi GBM Final Real-time Localization
  80. GRB 251006A (short): Glowbug gamma-ray detection
  81. GRB 251005C: COLIBRÍ optical observations
  82. GRB 251003A: LAST optical observations
  83. GRB 251002A: LAST optical observations
  84. GRB 251006A: Fermi GBM Final Real-time Localization
  85. GRB 251005C: AstroSat CZTI detection
  86. GRB 251005C: Swift/UVOT Upper Limits
  87. GRB 250902A: MSU cubesats detection
  88. GRB 251005C: Swift-XRT refined Analysis
  89. GRB 251005C: Fermi GBM Observation
  90. GRB 251005C: GOTO optical upper limits
  91. GRB 251005C: Swift detection of a burst
  92. GRB 251003A: J-band detection with WINTER
  93. GRB 251002A: NIR observations with WINTER
  94. GRB 251003A: Swift-BAT refined analysis
  95. GRB 251001B: NIR observations with WINTER
  96. GRB 251003A: Swift/UVOT Upper Limits
  97. GRB 251001A: AstroSat CZTI detection
  98. GRB 251001B: COLIBRÍ further observations and evidence of a multi-wavelength shallow decay
  99. GRB 251003A: Swift-XRT refined Analysis
  100. GRB 251003A: COLIBRÍ photometric redshift

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