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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"

5828 results found.

  1. Swift GRB 240905E: Global MASTER-Net observations report
  2. GRB 240905E: Swift detection of a burst
  3. GRB 240905D: AstroSat CZTI detection
  4. GRB 240905A: SVOM/GRM observation
  5. Fermi GRB 240905B: Global MASTER-Net observations report
  6. GRB 240905B: AstroSat CZTI detection and localization
  7. GRB 240825A: ATCA Detection of Radio Counterpart
  8. Swift GRB 240904A: Global MASTER-Net observations report
  9. Fermi trigger No 747163821: Global MASTER-Net observations report
  10. LIGO/Virgo/KAGRA S240902bq: Identification of a GW compact binary merger candidate
  11. Fermi trigger No 746923430: Global MASTER-Net observations report
  12. Fermi trigger No 746882332: Global MASTER-Net observations report
  13. Fermi trigger No 746587425: Global MASTER-Net observations report
  14. Fermi GRB 240828A: Global MASTER-Net observations report
  15. Fermi trigger No 746438824: Global MASTER-Net observations report
  16. LIGO/Virgo/KAGRA S240825ar: Identification of a GW compact binary merger candidate
  17. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  18. GRB 240821A: LCO optical observations
  19. GRB 240809A: Mondy and AbAO Optical Observations
  20. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  21. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  22. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  23. Fermi trigger No 745873283: Global MASTER-Net observations report
  24. Fermi trigger No 745871958: Global MASTER-Net observations report
  25. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  26. GRB 240815A: SVOM/GRM observation
  27. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  28. EP EP240816b: Global MASTER-Net observations report
  29. Fermi GRB 240814A: Global MASTER-Net observations report
  30. Fermi GRB 240814C: Global MASTER-Net observations report
  31. Fermi trigger No 745306088: Global MASTER-Net observations report
  32. Fermi trigger No 745220784: Global MASTER-Net observations report
  33. LIGO/Virgo/KAGRA S240813c: Identification of a GW compact binary merger candidate
  34. GRB 240809A: ATA radio non-detection
  35. GRB 240809A: ALMA detection
  36. GRB 240812B: AstroSat CZTI detection of a long burst
  37. IceCube-240808A: Upper limits from a search for additional neutrino events in IceCube
  38. Fermi trigger No 745057312: Global MASTER-Net observations report
  39. GRB 240811A: Swift detection of a burst
  40. GRB240809A: Liverpool Telescope optical follow-up observations
  41. GRB 240809A: REM detection of the optical afterglow
  42. GRB 240809A: GIT afterglow observations
  43. Swift GRB 240809A: Global MASTER-Net observations report
  44. GRB 240809A: JinShan optical observations
  45. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  46. EP EP240806a: Global MASTER-Net observations report
  47. GRB 240805A: ATCA Radio Upper Limits
  48. EP240806a: KAIT optical observations
  49. Fermi trigger No 744629911: Global MASTER-Net observations report
  50. Fermi Gamma-ray Burst Monitor trigger 240806402/744629911 is not a GRB
  51. Swift GRB 240805B: Global MASTER-Net observations report
  52. EP240801a: Osservatorio Astronomico Nastro Verde upper limit
  53. EP240801a: further SAO RAS optical observations
  54. EP240801a: Leavitt Observatory optical observations
  55. GRB 240727C: SVOM/GRM observation
  56. EP240801a: KAIT optical counterpart observations
  57. GRB 240801A: Fermi GBM Final Real-time Localization
  58. Fermi trigger No 744128417: Global MASTER-Net observations report
  59. Fermi GRB 240726A: Global MASTER-Net observations report
  60. GRB 240727A: Swift detection of a burst
  61. Fermi-LAT gamma-ray observations of IceCube-240725A
  62. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  63. IceCube-240721A: Upper limits from a search for additional neutrino events in IceCube
  64. Fermi GRB 240720A: Global MASTER-Net observations report
  65. Fermi GRB 240718A: Global MASTER-Net observations report
  66. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  67. IPN triangulation of GRB 240715A (short)
  68. EP-WXT flaring star and the optical flaring activity during its decay phase
  69. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  70. EP240703b: TRT optical upper limits
  71. EP240702a: TRT optical upper limits
  72. EP240703a: Kinder optical follow-up observations
  73. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  74. Fermi trigger No 740949590: Global MASTER-Net observations report
  75. GRB 240624A: Swift detection of a burst
  76. GRB 240619A: J-band detection with WINTER
  77. Fermi trigger No 740744838: Global MASTER-Net observations report
  78. LIGO/Virgo/KAGRA S240621eb: Identification of a GW compact binary merger candidate
  79. Fermi trigger No 740474239: Global MASTER-Net observations report
  80. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  81. Fermi trigger No 740430582: Global MASTER-Net observations report
  82. X-ray transient EP240414a: Chandra late time observation
  83. Fermi GRB 240616A: Global MASTER-Net observations report
  84. Fermi trigger No 740166710: Global MASTER-Net observations report
  85. Fermi GRB 240610A: Global MASTER-Net observations report
  86. Fermi Gamma-ray Burst Monitor trigger 739632045/240609556 is not a GRB
  87. Fermi trigger No 739632045: Global MASTER-Net observations report
  88. Fermi GRB 240607A: Global MASTER-Net observations report
  89. Fermi GRB 240604A: Global MASTER-Net observations report
  90. Fermi GRB 240605A: Global MASTER-Net observations report
  91. Fermi GRB 240603C: Global MASTER-Net observations report
  92. GRB 240603C: BALROG localization (Fermi Trigger 739102156 / GRB 240603423)
  93. GRB 240603C: Fermi GBM Final Real-time Localization
  94. GRB 240529A: continued SAO RAS optical observations
  95. Fermi GRB 240602A: Global MASTER-Net observations report
  96. GRB 240529A: AKO Optical Afterglow Follow-Up Observations
  97. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  98. Fermi GRB 240527A: Global MASTER-Net observations report
  99. LIGO/Virgo/KAGRA S240527fv: Identification of a GW compact binary merger candidate
  100. LIGO/Virgo/KAGRA S240527en: Identification of a GW compact binary merger candidate

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