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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

23151 results found.

  1. GRB 251025A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  2. GRB 251025A: SVOM/VT VHF optical upper limit
  3. GRB 251025A: SVOM detection of a faint burst
  4. GRB 251023C: Glowbug gamma-ray detection
  5. GRB 251022A: KAIT optical observations
  6. GRB 251024A: Swift detection of a burst
  7. GRB 251023B / EP251023b: COLIBRÍ Confirmation of the Fading Nature of the Optical Candidate
  8. GRB 251022A: COLIBRÍ Further Multi-frequency Optical Observations
  9. GRB 251023B: OHP/T193 optical observations
  10. GRB 251023C: AstroSat CZTI detection
  11. GRB 251022A: Swift-XRT detection of GOTO25iym
  12. GRB 251023C: CALET Gamma-Ray Burst Monitor detection
  13. GRB 251023A: Glowbug gamma-ray detection
  14. GRB 251023B: Glowbug gamma-ray detection
  15. EP251023a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at Teide Observatory
  16. GRB 251023B / EP#01709247298: COLIBRÍ optical counterpart candidate
  17. IPN triangulation of GRB 251016B
  18. GRB 251023B: CALET Gamma-Ray Burst Monitor detection
  19. EP#01709247298: Swift-XRT counterpart detection
  20. EP251023a: COLIBRÍ optical observations
  21. GRB 251013C: further SAO RAS optical observations
  22. GRB 251022A: COLIBRÍ optical observations
  23. GRB 251022A: DDOTI Optical Detection
  24. GRB 251023B / MAXI J0451+122: MAXI/GSC detection
  25. EP251023a: GSP Optical Counterpart Detection
  26. EP/WXT 01709247295: GOTO optical afterglow candidate.
  27. GRB 251022A: GOTO optical counterpart detection
  28. GRB 251022A: Fermi-LAT detection
  29. GRB 251021A/EP251021b: Fermi-GBM Sub-Threshold Detection
  30. EP251021b: BOOTES-7 optical upper limit
  31. GRB 250911A: MAXI/GSC detection
  32. GRB 251016A: SVOM/ECLAIRs refined analysis
  33. LIGO/Virgo/KAGRA S251021u: Identification of a GW compact binary merger candidate
  34. Fermi-LAT gamma-ray observations of IceCube-251018A
  35. GRB 251017A : RAPAS follow-up observations
  36. GRB 251017A: COLIBRÍ optical observations of a late plateau
  37. IceCube-251018A: DDOTI Optical Upper Limit
  38. GRB 251017A: Swift-BAT refined analysis
  39. GRB 251018A: Fermi GBM Observation
  40. GRB 251018A: BOOTES-5 and BOOTES-7 early optical detections
  41. GRB 251018A: Swift-XRT refined Analysis
  42. LIGO/Virgo/KAGRA S251018bi: Identification of a GW compact binary merger candidate
  43. GRB 251017A: VLT/MUSE spectroscopic redshift z = 4.327
  44. GRB 251017A: COLIBRÍ photometric redshift
  45. GRB 251017A: Swift-XRT refined Analysis
  46. GRB 251018A: TRT optical afterglow detection
  47. GRB 251018A: Swift detection of a burst with an optical counterpart
  48. GRB 251017A: J-band detection with WINTER
  49. GRB 251017A: Glowbug gamma-ray detection
  50. GRB 251017A : MITSuME Akeno optical afterglow candidate detection
  51. Swift Trigger 1404295 is not a GRB
  52. GRB 251016A: AstroSat CZTI detection of a short burst
  53. GRB 251017A: COLIBRÍ Early Afterglow Detection
  54. GRB 251016B: AstroSat CZTI detection
  55. GRB 251017A: BOOTES-5/JGT early optical afterglow detection
  56. GRB 251017A: Swift detection of a burst with an optical counterpart
  57. GRB 251016A: CALET Gamma-Ray Burst Monitor detection
  58. GRB 251016B: CALET Gamma-Ray Burst Monitor detection
  59. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) observations of a strong and late rebrightening of the optical counterpart
  60. GRB 251007B: Swift-BAT refined analysis
  61. GRB 251014D: Swift-BAT refined analysis
  62. GRB 251016A: BOOTES-6/DPRT optical upper limit
  63. GRB 251016A: Glowbug gamma-ray detection of a short burst
  64. sb25101602: Swift-XRT counterpart detection
  65. GRB 251014B: PRIME J-band upper limit
  66. GRB 251013C: Kilonova-Catcher optical afterglow detection
  67. GRB 251013D: Swift/UVOT Observations
  68. GRB 251013C: Swift/UVOT Detection
  69. Konus-Wind detection of GRB 251007A
  70. GRB 251013C: SVOM/ECLAIRs refined analysis
  71. Swift Trigger 1404295: possible GRB 251015A
  72. GRB 251014D: BOOTES-6/DPRT optical upper limit
  73. GRB 251013C: MAO/AZT-22 optical observations
  74. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) further multi-band optical observations
  75. GRB 251014A: Swift-BAT refined analysis
  76. GRB 251013C: OHP/T193 further optical observations and possible color evolution
  77. GRB 251014D: Swift detection of a burst
  78. GRB 251014A: PRIME near-infrared upper limits
  79. GRB 251014A: Glowbug gamma-ray detection of a likely short burst
  80. GRB 251012A: Glowbug gamma-ray detection of a likely short burst
  81. GRB 251013D: LAST optical upper limit on Swift/BAT-GUANO localization
  82. GRB 251013C: Early and late-time optical counterpart detection by LCO
  83. LIGO/Virgo/KAGRA S251014cn: NED Galaxies in the 3-Initial Localization Volume
  84. GRB 251014A: DDOTI Upper Limit
  85. GRB 251013C NUTTelA-TAO / BSTI Early Measurements
  86. LIGO/Virgo/KAGRA S251014cn: Identification of a GW compact binary merger candidate
  87. GRB 251013C: ULL-ASTRO-MASTER detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  88. GRB 251013A: CALET Gamma-Ray Burst Monitor detection
  89. GRB 251013C: ABObservatory optical observations
  90. GRB 251014A: SAO RAS optical upper limit
  91. GRB 251014A: Fermi GBM Observation
  92. GRB 251013C: J band observations by SYSU 80cm infrared telescope
  93. GRB 251013C: AstroSat CZTI detection
  94. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) detection of the optical counterpart
  95. GRB 251013C: DDOTI detection of the optical afterglow
  96. GRB 251014A: Swift detection of a possibly-short burst
  97. Fermi trigger No 782044789: Global MASTER-Net observations report
  98. GRB 251013C: Swift-XRT counterpart detection
  99. GRB 251013C: GOTO optical afterglow detection
  100. GRB 251013C: SAO RAS optical observations

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