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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"

32543 results found.

  1. LIGO/Virgo/KAGRA S240908bs: Identification of a GW compact binary merger candidate
  2. LIGO/Virgo/KAGRA S240907cg: Updated Sky localization
  3. GRB 240801A: SVOM/GRM observation
  4. LIGO/Virgo/KAGRA S240907cg: Identification of a GW compact binary merger candidate
  5. GRB 240905E: GIT optical upper limit
  6. GRB 240905E: Gaoyazi/GOT optical upper limits
  7. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  8. GRB 240905B: Fermi-LAT detection
  9. GRB 240905B: Swift ToO observations
  10. GRB 240905E: J-band observations with WINTER
  11. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  12. GRB 240905E: AKO Optical Upper Limit
  13. GRB 240905E: SVOM/C-GFT optical upper limit
  14. GRB 240905E: OHP/MISTRAL T193 optical upper limit
  15. Fermi GRB 240905D: Global MASTER-Net observations report
  16. Fermi GRB 240905A: Global MASTER-Net observations report
  17. GRB 240905E: NOT optical upper limits
  18. GRB 240905E: REM optical/NIR upper limits
  19. GRB 240905E: SVOM/GRM observation
  20. GRB 240905E: LCOGT Optical Upper Limit
  21. GRB 240905E: Swift/UVOT Upper Limits
  22. GRB 240905E: SAO RAS optical upper limit
  23. GRB 240825A: Montarrenti Observatory optical follow-up observations
  24. GRB 240905E: Nanshan/HMT optical upper limit
  25. Swift GRB 240905E: Global MASTER-Net observations report
  26. GRB 240819A: Optical upper limits from TESS
  27. GRB 240905D: AstroSat CZTI detection
  28. GRB 240905A: SVOM/GRM observation
  29. Fermi GRB 240905B: Global MASTER-Net observations report
  30. GRB 240905B: AstroSat CZTI detection and localization
  31. GRB 240825A: ATCA Detection of Radio Counterpart
  32. Swift GRB 240904A: Global MASTER-Net observations report
  33. GRB 240828A: SVOM/GRM observation
  34. Fermi Gamma-ray Burst Monitor trigger 240831A is not a GRB
  35. LIGO/Virgo/KAGRA S240902bq: Updated Sky localization
  36. GRB 240828A: GECAM detection
  37. LIGO/Virgo/KAGRA S240902bq: Identification of a GW compact binary merger candidate
  38. GRB 240825A: Magnitude Correction in SVOM/C-GFT Optical Observations
  39. GRB 240825A: MeerLICHT afterglow detection
  40. GRB 240828A: SAO RAS AS-500(2) optical observations
  41. GRB 240821A: VLT spectroscopic observations
  42. GRB 240825A: TSHAO Optical Upper Limit
  43. GRB 240829B: GRBAlpha detection
  44. GRB240828B: REM optical/NIR upper limits
  45. GRB 240828B: AbAO optical upper limit
  46. GRB 240825A: SOAR observations
  47. GRB 240828B: Mephisto optical upper limit
  48. GRB 240828B: GRANDMA Optical Upper Limit
  49. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  50. LIGO/Virgo/KAGRA S240830gn: Updated Sky localization and EM Bright Classification
  51. GRB 240829A: Swift-BAT refined analysis
  52. GRB 240825A: Swift-BAT refined analysis
  53. LIGO/Virgo/KAGRA S240830gn: Identification of a GW compact binary merger candidate
  54. GRB 240825A: MeerKAT detection
  55. GRB 240828B: J-band upper limit from WINTER
  56. GRB 240828B: GMG Optical Upper Limit
  57. GRB 240828A: KAIT continued optical observations
  58. GRB 240828B: GWAC-F50A optical upper limit
  59. GRB 240828B: SVOM/C-GFT optical upper limit
  60. GRB 240828B: SAO RAS optical upper limit
  61. GRB 240828B: KAIT optical upper limit
  62. GRB 240828A: SAO RAS optical observations
  63. GRB 240828A: Fermi GBM Observation
  64. GRB 240629A: First GRB Detected by BurstCube
  65. GRB 240828A: KAIT Optical Afterglow Candidate
  66. GRB 240825A: SVOM/VT optical detection
  67. GRB 240825A: further SAO RAS optical observations
  68. GRB 240825A: iTelescope optical observations
  69. GRB 240828A: Fermi-LAT detection
  70. GRB 240828A: Tiled Swift observations
  71. GRB 240828A: AstroSat CZTI detection of a long burst
  72. GRB 240825A: Upper limits from a neutrino search with IceCube
  73. GRB 240819A as a likely X-Ray Flash
  74. GRB 240828B: Swift ToO observations
  75. GRB 240821A: PRIME near-infrared observations
  76. GRB 240825A: VLA detection
  77. Fermi GRB 240828A: Global MASTER-Net observations report
  78. SVOM GRB 240821A: optical afterglow discovery
  79. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  80. GRB 240825A: GECAM detection
  81. GRB 240825A: ALMA detection
  82. GRB 240825A: SAO RAS optical observations
  83. GRB 240824A: GIT optical upper limit
  84. GRB 240819A: Swift afterglow confirmation
  85. GRB 240825A: TNG optical photometry and spectroscopy
  86. LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
  87. LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
  88. GRB 240825A: NUTTelA-TAO / BSTI Optical Limits
  89. GRB 240825A: GMG Continued Optical Observation on the Second Night
  90. GRB 240824B: Ondrejov D50 optical limit
  91. GRB 240825A: KAIT optical observations
  92. GRB 240825A: PRIME near-infrared detection
  93. Konus-Wind detection of GRB 240825A (bright/long)
  94. GRB 240825A: Fermi GBM Observation
  95. GRB 240825A : MISTRAL/T193 OHP optical follow-up of the afterglow
  96. GRB 240825A: AKO Optical Follow-Up Observations
  97. GRB 240825A: AstroSat CZTI detection of the long bright burst
  98. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  99. GRB 240825A: Swift/UVOT Detection
  100. GRB 240825A: REM detection of the optical/NIR afterglow

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