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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').
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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"

32508 results found.

  1. GRB 240821A: Swift-XRT observations
  2. GRB 240821A: REM optical/NIR upper limits
  3. GRB 240821A: LCO optical observations
  4. GRB 240821A: JinShan optical upper limits
  5. GRB 240809A: Mondy and AbAO Optical Observations
  6. GRB 240821A: SVOM/VT follow-up and optical upper limit
  7. GRB 240821A: GMG Optical Upper Limit
  8. Fermi GRB 240821A: Global MASTER-Net observations report
  9. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  10. GRB 240821A: Fermi GBM Observation
  11. GRB 240821A: Swift ToO observations
  12. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  13. GRB240821A: EIRSAT-1 GMOD Detection
  14. GRB240821B: First GRB Detected by EIRSAT-1 GMOD
  15. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  16. Fermi GRB 240821B: Global MASTER-Net observations report
  17. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  18. GRB 240821A: SVOM/GRM observation
  19. GRB 240821A: SVOM/GRM observation
  20. GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
  21. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  22. GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
  23. GRB 240819A: Swift-XRT observations
  24. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  25. EP240820a: TRT optical upper limit
  26. GRB 240819A: KAIT optical upper limit
  27. EP240816a: PRIME upper limits
  28. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  29. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  30. GRB 240819A: Swift ToO observations
  31. GRB 240814A: SVOM/GRM observation
  32. EP240816b: Liverpool Telescope optical follow-up observations
  33. GRB 240814C: SVOM/GRM observation
  34. IceCube-240721A: AT2023qqp and AT2024pge likely unrelated
  35. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  36. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  37. EP240816b: KAIT optical upper limit
  38. GRB 240814B: GRBAlpha detection
  39. EP EP240816b: Global MASTER-Net observations report
  40. EP240816b: TRT optical upper limit
  41. Fermi GRB 240814A: Global MASTER-Net observations report
  42. Fermi GRB 240814C: Global MASTER-Net observations report
  43. Fermi GRB 240814B: Global MASTER-Net observations report
  44. GRB 240812B: SVOM/GRM observation
  45. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  46. LIGO/Virgo/KAGRA S240813d: Updated Sky localization
  47. Konus-Wind detection of GRB 240811A
  48. Konus-Wind detection of GRB 240810A
  49. LIGO/Virgo/KAGRA S240813d: Identification of a GW compact binary merger candidate
  50. LIGO/Virgo/KAGRA S240813c: Updated Sky localization
  51. LIGO/Virgo/KAGRA S240813c: Identification of a GW compact binary merger candidate
  52. GRB 240809A: Correction to the VLA source position in GCN 37158
  53. GRB 240810A: SVOM/GRM observation
  54. GRB 240809A: ATA radio non-detection
  55. GRB 240809A : RAPAS follow-up observations
  56. GRB 240809A: VLA detection
  57. GRB 240809A: ALMA detection
  58. IPN triangulation of GRB 240810A (short)
  59. GRB 240811A: Swift-BAT refined analysis
  60. GRB 240809A: Swift-BAT refined analysis
  61. EP240807a: PRIME H-band upper limits
  62. IceCube-240808A: Upper limits from a search for additional neutrino events in IceCube
  63. GRB 240811A: Bassano Bresciano Observatory upper limit
  64. GRB 240811A: Swift/UVOT Upper Limits
  65. EP240801a: Assy-Turgen optical observations
  66. Fermi GRB 240810A: Global MASTER-Net observations report
  67. GRB 240811A: LCOGT Optical Upper Limit
  68. GRB 240811A: Upper limits with Mephisto
  69. Konus-Wind detection of GRB 240809A
  70. Swift GRB 240811A: Global MASTER-Net observations report
  71. GRB240809A: Liverpool Telescope optical follow-up observations
  72. GRB 240809A: REM detection of the optical afterglow
  73. GRB 240809A: Bassano Bresciano Observatory optical observations
  74. Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
  75. GRB 240809A: Conclusive redshift from VLT
  76. Fermi-LAT gamma-ray observations of IceCube-240808A
  77. GRB 240809A: KAIT optical observations
  78. GRB 240808A: AstroSat CZTI detection
  79. GRB 240809A: GIT afterglow observations
  80. GRB 240809A: Swift/UVOT Detection
  81. GRB 240809A: Tentative redshift from NOT
  82. IPN triangulation of GRB 240807A / EP 240807a
  83. LIGO/Virgo/KAGRA S240807h: Updated Sky localization and EM Bright Classification
  84. X-ray Transient EP240807a: PRIME near-infrared upper limits
  85. Swift GRB 240809A: Global MASTER-Net observations report
  86. GRB 240809A: JinShan optical observations
  87. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  88. GRB 240809A: SVOM/GRM observation
  89. GRB 240807A: SVOM/GRM observation
  90. EP-WXT trigger 01709018832: SVOM/C-GFT observations of the star flare
  91. EP240807a: STEP/T80S optical limits
  92. GRB 240807B: AstroSat CZTI detection of a short burst
  93. EP EP240807a: Global MASTER-Net observations report
  94. EP EP240806a: Global MASTER-Net observations report
  95. GRB 240801A: GRBAlpha detection
  96. GRB 240710B: VZLUSAT-2 detection
  97. GRB 240805A: ATCA Radio Upper Limits
  98. EP240807a/GRB 240807A: EP-FXT detection of the X-ray emission
  99. S240807h: Identification of a GW compact binary merger candidate
  100. EP240802a/GRB240802A: KAIT optical upper limit

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