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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"

5401 results found.

  1. IceCube-250102A: Upper limits from a search for additional neutrino events in IceCube
  2. Swift GRB 250103B: Global MASTER-Net observations report
  3. GRB 250101a: Liverpool Telescope optical follow-up
  4. GRB 250103B: SVOM detection of a long burst
  5. GRB 250103A: Xinglong 2.16m Optical Candidate
  6. Fermi GRB 250102A: Global MASTER-Net observations report
  7. GRB 250103A: GOTO optical upper limit
  8. IceCube Alert 250102.58: Global MASTER-Net observations report
  9. GRB 250101A: LCO optical counterpart detection
  10. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  11. Konus-Wind detection of GRB 241228A
  12. GRB 241229A: GOTO optical upper limits
  13. Fermi GRB 241228B: Global MASTER-Net observations report
  14. GRB 241228A: Fermi GBM Observation
  15. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  16. GRB 241228A: Swift detection of a burst
  17. Fermi trigger No 756678579: Global MASTER-Net observations report
  18. EP241223a: Global MASTER-Net observations report
  19. Konus-Wind detection of GRB 241204A (short/hard)
  20. GRB 241217A/EP241217b: REM optical/NIR upper limits
  21. GRB 241218a: Liverpool Telescope optical follow-up
  22. EP241217a: Liverpool Telescope optical follow-up
  23. GRB 241218A: LCOGT Optical Upper Limit
  24. EP241217a: Global MASTER-Net observations report
  25. EP241217A: Non-detection from Fermi-GBM Observations
  26. GRB 241214A: GRBAlpha detection
  27. EP241217a: Gemini-North detection of the likely optical counterpart
  28. EP241217a: EP detection of an X-ray transient
  29. GRB 241213B: MAXI/GSC detection
  30. GRB 241213A: REM optical/NIR upper limits
  31. GRB 241212A : SVOM/VT bright optical afterglow
  32. Konus-Wind detection of GRB 241209B
  33. GRB 241209B: GRBAlpha detection
  34. GRB 241206C: GRBAlpha detection
  35. Fermi Gamma-ray Burst Monitor trigger 755485387 / 241210044 is not a GRB
  36. EP241208a: Global MASTER-Net observations report
  37. Fermi trigger No 755485387: Global MASTER-Net observations report
  38. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  39. Fermi GRB 241209C: Global MASTER-Net observations report
  40. LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
  41. Fermi GRB 241209A: Global MASTER-Net observations report
  42. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  43. Fermi GRB 241207B: Global MASTER-Net observations report
  44. Fermi GRB 241207A: Global MASTER-Net observations report
  45. GRB 241206C: SVOM/GRM observation of a likely short burst
  46. GRB 241204A: DDOTI Upper Limits on the Afterglow
  47. GRB 241204A: Fermi GBM Observation
  48. Fermi GRB 241204A: Global MASTER-Net observations report
  49. GRB 241204A: Fermi-LAT detection
  50. EP241202b: Kinder optical counterpart candidate
  51. EP241202b: Global MASTER-Net observations report
  52. EP241201a: Kinder optical counterpart candidate
  53. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  54. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  55. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  56. EP241126a: GSP detects optical counterpart
  57. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  58. Konus-Wind detection of GRB 241117A
  59. IPN triangulation of GRB 241117A
  60. GRB 241114B: Insight-HXMT/HE detection
  61. Fermi GRB 241118A: Global MASTER-Net observations report
  62. GRB 241117A: Fermi GBM Detection
  63. Fermi GRB 241117A: Global MASTER-Net observations report
  64. GRB 241117A: Fermi GBM Final Real-time Localization
  65. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  66. EP241113a: Swift XRT weak detection
  67. GRB 241113A: J-band observations with WINTER
  68. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  69. GRB 241113A: KAIT optical observations
  70. EP241113b: Global MASTER-Net observations report
  71. GRB 241113A: REM detection of the optical/NIR afterglow
  72. Fermi trigger No 753166198: Global MASTER-Net observations report
  73. GRB 241112B: AbAO optical upper limit
  74. IPN triangulation of GRB 241107A (short/hard)
  75. Fermi trigger No 752878030: Global MASTER-Net observations report
  76. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  77. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  78. EP241107a: AKO Optical Afterglow Follow-Up Observations
  79. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  80. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  81. EP241107a: AKO Optical Afterglow Detection
  82. EP241101a: CrAO ZTSH optical observations
  83. GRB 241030A: Mondy optical observations
  84. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  85. GRB 240511A: LCO upper limits
  86. Fermi GRB 241105A: Global MASTER-Net observations report
  87. EP241103a: GIT optical upper limit
  88. EP241021a: OHP/T193 further optical observations
  89. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  90. EP241103a: GOTO optical upper limit
  91. EP241103a: Swift XRT detection and improved X-ray position
  92. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  93. EP241103a: GSP optical upper limit
  94. EP241103A: LCO optical observations
  95. EP241103a: Global MASTER-Net observations report
  96. GRB 241030A: Rapid release of TESS data.
  97. GRB241030A: OHP/T193 optical observations
  98. Fermi trigger No 752083996: Global MASTER-Net observations report
  99. EP EP241030a: Global MASTER-Net observations report
  100. Fermi trigger No 752006065: Global MASTER-Net observations report

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