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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"

5843 results found.

  1. LIGO/Virgo/KAGRA S240908bs: Identification of a GW compact binary merger candidate
  2. LIGO/Virgo/KAGRA S240907cg: Identification of a GW compact binary merger candidate
  3. GRB 240905E: GIT optical upper limit
  4. GRB 240905E: Gaoyazi/GOT optical upper limits
  5. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  6. GRB 240905E: J-band observations with WINTER
  7. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  8. Fermi GRB 240905D: Global MASTER-Net observations report
  9. Fermi GRB 240905A: Global MASTER-Net observations report
  10. GRB 240905E: NOT optical upper limits
  11. GRB 240902B: AstroSat CZTI detection of a long burst
  12. GRB 240902A: AstroSat CZTI detection of a long burst
  13. GRB 240905E: SVOM/GRM observation
  14. GRB 240905E: SAO RAS optical upper limit
  15. GRB 240905E: Nanshan/HMT optical upper limit
  16. Swift GRB 240905E: Global MASTER-Net observations report
  17. GRB 240905E: Swift detection of a burst
  18. GRB 240905D: AstroSat CZTI detection
  19. GRB 240905A: SVOM/GRM observation
  20. Fermi GRB 240905B: Global MASTER-Net observations report
  21. GRB 240905B: AstroSat CZTI detection and localization
  22. GRB 240825A: ATCA Detection of Radio Counterpart
  23. Swift GRB 240904A: Global MASTER-Net observations report
  24. Fermi trigger No 747163821: Global MASTER-Net observations report
  25. LIGO/Virgo/KAGRA S240902bq: Identification of a GW compact binary merger candidate
  26. Fermi trigger No 746923430: Global MASTER-Net observations report
  27. Fermi trigger No 746882332: Global MASTER-Net observations report
  28. Fermi trigger No 746587425: Global MASTER-Net observations report
  29. Fermi GRB 240828A: Global MASTER-Net observations report
  30. Fermi trigger No 746438824: Global MASTER-Net observations report
  31. LIGO/Virgo/KAGRA S240825ar: Identification of a GW compact binary merger candidate
  32. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  33. GRB 240821A: LCO optical observations
  34. GRB 240809A: Mondy and AbAO Optical Observations
  35. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  36. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  37. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  38. Fermi trigger No 745873283: Global MASTER-Net observations report
  39. Fermi trigger No 745871958: Global MASTER-Net observations report
  40. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  41. GRB 240815A: SVOM/GRM observation
  42. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  43. EP EP240816b: Global MASTER-Net observations report
  44. Fermi GRB 240814A: Global MASTER-Net observations report
  45. Fermi GRB 240814C: Global MASTER-Net observations report
  46. Fermi trigger No 745306088: Global MASTER-Net observations report
  47. Fermi trigger No 745220784: Global MASTER-Net observations report
  48. LIGO/Virgo/KAGRA S240813c: Identification of a GW compact binary merger candidate
  49. GRB 240809A: ATA radio non-detection
  50. GRB 240809A: ALMA detection
  51. GRB 240812B: AstroSat CZTI detection of a long burst
  52. IceCube-240808A: Upper limits from a search for additional neutrino events in IceCube
  53. Fermi trigger No 745057312: Global MASTER-Net observations report
  54. GRB 240811A: Swift detection of a burst
  55. GRB240809A: Liverpool Telescope optical follow-up observations
  56. GRB 240809A: REM detection of the optical afterglow
  57. GRB 240809A: GIT afterglow observations
  58. Swift GRB 240809A: Global MASTER-Net observations report
  59. GRB 240809A: JinShan optical observations
  60. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  61. EP EP240806a: Global MASTER-Net observations report
  62. GRB 240805A: ATCA Radio Upper Limits
  63. EP240806a: KAIT optical observations
  64. Fermi trigger No 744629911: Global MASTER-Net observations report
  65. Fermi Gamma-ray Burst Monitor trigger 240806402/744629911 is not a GRB
  66. Swift GRB 240805B: Global MASTER-Net observations report
  67. EP240801a: Osservatorio Astronomico Nastro Verde upper limit
  68. EP240801a: further SAO RAS optical observations
  69. EP240801a: Leavitt Observatory optical observations
  70. GRB 240727C: SVOM/GRM observation
  71. EP240801a: KAIT optical counterpart observations
  72. GRB 240801A: Fermi GBM Final Real-time Localization
  73. Fermi trigger No 744128417: Global MASTER-Net observations report
  74. Fermi GRB 240726A: Global MASTER-Net observations report
  75. GRB 240727A: Swift detection of a burst
  76. Fermi-LAT gamma-ray observations of IceCube-240725A
  77. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  78. IceCube-240721A: Upper limits from a search for additional neutrino events in IceCube
  79. Fermi GRB 240720A: Global MASTER-Net observations report
  80. Fermi GRB 240718A: Global MASTER-Net observations report
  81. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  82. IPN triangulation of GRB 240715A (short)
  83. EP-WXT flaring star and the optical flaring activity during its decay phase
  84. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  85. EP240703b: TRT optical upper limits
  86. EP240702a: TRT optical upper limits
  87. EP240703a: Kinder optical follow-up observations
  88. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  89. Fermi trigger No 740949590: Global MASTER-Net observations report
  90. GRB 240624A: Swift detection of a burst
  91. GRB 240619A: J-band detection with WINTER
  92. Fermi trigger No 740744838: Global MASTER-Net observations report
  93. LIGO/Virgo/KAGRA S240621eb: Identification of a GW compact binary merger candidate
  94. Fermi trigger No 740474239: Global MASTER-Net observations report
  95. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  96. Fermi trigger No 740430582: Global MASTER-Net observations report
  97. X-ray transient EP240414a: Chandra late time observation
  98. Fermi GRB 240616A: Global MASTER-Net observations report
  99. Fermi trigger No 740166710: Global MASTER-Net observations report
  100. Fermi GRB 240610A: Global MASTER-Net observations report

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