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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"

32764 results found.

  1. GRB 251013D: Fermi GBM Observation
  2. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) further multi-band optical observations
  3. GRB 251014A: Swift-BAT refined analysis
  4. GRB 251013C: OHP/T193 further optical observations and possible color evolution
  5. GRB 251013C: Calapai Observatory, Massa S. Giorgio (Messina), optical observation
  6. GRB 251014A: PRIME near-infrared upper limits
  7. GRB 251014A: Glowbug gamma-ray detection of a likely short burst
  8. GRB 251014A: VLT/FORS2 Optical Observation
  9. GRB 251013C: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an bright optical counterpart
  10. GRB 251012A: Glowbug gamma-ray detection of a likely short burst
  11. GRB 251013C: MarSEC, optical afterglow photometry
  12. GRB 251013C: OHP/T193 optical afterglow photometry and spectroscopy
  13. GRB 251014B: Swift ToO observations
  14. GRB 251013D: LAST optical upper limit on Swift/BAT-GUANO localization
  15. GRB 251014B: Swift/BAT-GUANO arcminute localization of a short burst
  16. GRB 251013C: Bassano Bresciano Observatory optical observations
  17. GRB 251013C: Early and late-time optical counterpart detection by LCO
  18. GRB 251013C: Fermi GBM Observation
  19. GRB 251013D: Swift ToO observations
  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 251013C: Asiago optical observations
  25. GRB 251013A: CALET Gamma-Ray Burst Monitor detection
  26. GRB 251013C: ABObservatory optical observations
  27. GRB 251014A: SAO RAS optical upper limit
  28. GRB 251014A: Fermi GBM Observation
  29. GRB 251013C: J band observations by SYSU 80cm infrared telescope
  30. GRB 251013C: EP-FXT counterpart detection
  31. GRB 251013C: AstroSat CZTI detection
  32. GRB 251011A: Swift/BAT-GUANO arcminute localization of a burst
  33. GRB 251013D: Swift/BAT-GUANO arcminute localization of a burst
  34. GRB 251013C: ALMA detection
  35. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) detection of the optical counterpart
  36. GRB 251013C: DDOTI detection of the optical afterglow
  37. GRB 251013C: SLKT optical afterglow photometry
  38. Swift GRB 251014A: Global MASTER-Net observations report
  39. Fermi GRB 251013C: Global MASTER-Net observations report
  40. Fermi GRB 251013B: Global MASTER-Net observations report
  41. Fermi GRB 251013D: Global MASTER-Net observations report
  42. GRB 251013C: Swift-XRT counterpart detection
  43. GRB 251013C: GOTO optical afterglow detection
  44. GRB 251013C: SAO RAS optical observations
  45. GRB 251013C: LCO optical afterglow detection
  46. GRB 251013C: Optical Observations via Virtual Telescope Project, Italy
  47. GRB 251013C: NOT spectroscopic redshift z = 0.572
  48. GRB 251013C: LAST detection of optical counterpart
  49. GRB 251013C: BOOTES-6 early optical detection
  50. GRB 251013C: SVOM/VT optical observation
  51. GRB 251013C: SVOM detection of a burst
  52. LIGO/Virgo/KAGRA S251013x: Updated Sky localization and Source Classification
  53. GRB 251013B: SVOM/GRM observation
  54. GRB 251013A: SVOM/GRM observation
  55. GRB 251003A: Mondy optical upper limit
  56. MASTER OT J011025.98-583210.6 : SVOM/VT optical observation
  57. Fermi GRB 251013A: Global MASTER-Net observations report
  58. LIGO/Virgo/KAGRA S251013x: Identification of a GW compact binary merger candidate
  59. GRB 251011B inspection: MASTER orphan GRB detection
  60. GRB 251011A: Insight-HXMT detection
  61. GRB 251011B: Swift/UVOT Upper Limits
  62. Fermi GRB 251011A: Global MASTER-Net observations report
  63. GRB 251011B: SVOM/GRM observation
  64. GRB 251011B: Fermi GBM Observation
  65. GRB 251011B : MASTER optical observations
  66. GRB 251010A: AstroSat CZTI detection
  67. GRB 251011A: AstroSat CZTI detection
  68. GRB 251009B: SVOM/GRM observation of short GRB
  69. GRB 251007B: Swift/UVOT Upper Limits
  70. GRB251007A: Swift/UVOT Detection
  71. GRB 251009A: GECAM-B detection of a short burst
  72. GRB 251009A: Insight-HXMT detection of a short burst
  73. GRB 251009B (short): Glowbug gamma-ray detection
  74. GRB 251007A: Swift-BAT refined analysis
  75. GRB 251009A: SVOM/GRM observation of short GRB with possible tail emission
  76. GRB 251007A: SVOM/GRM observation
  77. GRB 251007A: Insight-HXMT detection
  78. GRB 251006A: CALET Gamma-Ray Burst Monitor detection
  79. GRB 251007B - SVOM/ECLAIRs refined analysis
  80. GRB 250916A: TERI Gamma-ray detection
  81. GRB 250919A: TERI gamma-ray detection
  82. EP251006a: Global MASTER-Net observations report
  83. GRB 251006A: Fermi GBM Observation
  84. GRB 251002A - SVOM/ECLAIRs refined analysis
  85. GRB 251003A: Fermi GBM Observation
  86. GRB 251006B: Fermi GBM Observation
  87. GRB 251007B: COLIBRÍ optical upper limit
  88. GRB 251007A: AstroSat CZTI detection
  89. GRB 251006B/EP251006a: EP-FXT afterglow detection
  90. GRB 250917B: iTelescope T-26 upper limit
  91. EP250911a: Koshka Zeiss-1000 Optical Upper Limit
  92. GRB 251007B: SVOM/VT optical candidate
  93. GRB 251007A: NOT optical observations
  94. GRB 251007A: AKO Optical Upper Limit
  95. GRB 251007A: CALET Gamma-Ray Burst Monitor detection
  96. GRB 251006B: Insight-HXMT detection
  97. GRB 251007A: SVOM/C-GFT optical observations
  98. GRB 251005C: PRIME J-band upper limit
  99. Swift GRB 251007B: Global MASTER-Net observations report
  100. GRB 251007A: Glowbug gamma-ray detection

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