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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

43965 results found.

  1. GRB 241228B: SAO RAS optical observations
  2. GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
  3. GRB 241229A: SAO RAS optical observations
  4. IceCube-Cascade 241228A: Upper limits from a search for additional neutrino events in IceCube
  5. GRB 241229B: SVOM/VT optical candidate
  6. GRB 241229A: Swift-XRT observations
  7. Konus-Wind detection of GRB 241228A
  8. GRB 241229A: EP-FXT afterglow candidates
  9. EP240702a: 7DT Optical upper limits
  10. GRB 240606B: 7DT Optical upper limits
  11. Fermi trigger No 757231333: Global MASTER-Net observations report
  12. LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate
  13. GRB 241229B: Swift-BAT refined analysis
  14. LIGO/Virgo/KAGRA S241225v: Updated Sky localization
  15. LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification
  16. Fermi Gamma-ray Burst Monitor trigger 757207662/241229978 (GRB 241229C) is not a GRB
  17. GRB241229B: UVOT upper limits
  18. GRB 241229C: Fermi GBM Final Real-time Localization
  19. GRB 241228B: Fermi GBM Observation
  20. GRB 241228B: Swift-XRT afterglow detection
  21. GRB 241229B: Fermi GBM Observation
  22. GRB 241229A: Swift ToO observations
  23. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  24. GRB 241228A: Mondy optical afterglow observations
  25. GRB 241229B: Swift-XRT refined Analysis
  26. IceCube-241224A: No transient candidates from the Zwicky Transient Facility
  27. Swift GRB 241229B: Global MASTER-Net observations report
  28. GRB 241229A: GOTO optical upper limits
  29. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  30. GRB 241228A: NOT optical upper limits
  31. GRB 241228B: LCO optical observation
  32. GRB 241228A: Swift-BAT refined analysis
  33. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  34. GRB 241229B: Swift detection of a burst
  35. GRB 241229B: Fermi GBM Final Real-time Localization
  36. GRB 241229A: SVOM detection of a long burst
  37. Fermi GRB 241228B: Global MASTER-Net observations report
  38. GRB 241228A: Fermi GBM Observation
  39. GRB241228B: GROWTH-India Telescope optical observations
  40. Swift GRB 241228A: Global MASTER-Net observations report
  41. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  42. GRB 241228B: GOTO24jmz optical follow-up observations
  43. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  44. GRB 241228A: GROWTH-India telescope optical upper limit
  45. GRB 241228B: Swift ToO observations
  46. GRB 241228B: TRT optical counterpart confirmation
  47. GRB 241228A: Swift-XRT refined Analysis
  48. GRB 241228B: GOTO possible optical counterpart candidate
  49. GRB 241228A: Enhanced Swift-XRT position
  50. GRB 241228B: Fermi GBM Final Real-time Localization
  51. GRB 241228A: Swift detection of a burst
  52. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  53. LIGO/Virgo/KAGRA S241225c: Two counterpart neutrino candidates from IceCube neutrino searches
  54. GRB 241223A: GRBAlpha detection
  55. GRB 241212A: VZLUSAT-2 detection
  56. GRB 241217A/EP241217b: continued SOAR observations
  57. Fermi GRB 241226A: Global MASTER-Net observations report
  58. GRB 241226A: Fermi GBM Final Real-time Localization
  59. EP241223a: Mondy AZT-33IK optical observations
  60. GRB 241029A: LCO optical observation
  61. GRB 241223A: Swift-XRT observations
  62. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  63. GRB 241029A: AbAO AS-32 optical observations
  64. GRB 241223A: Fermi GBM Detection
  65. Fermi trigger No 756678579: Global MASTER-Net observations report
  66. LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate
  67. EP241223a
  68. IceCube-241224A - IceCube observation of a high-energy neutrino candidate track-like event
  69. IceCube Alert 241224.30: Global MASTER-Net observations report
  70. GRB 241219A: SVOM/GRM observation
  71. EP241223a: Global MASTER-Net observations report
  72. EP241223a: EP-WXT detection of a fast X-ray transient
  73. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  74. GRB241113A: 7DT Optical upper limits
  75. Fermi Gamma-ray Burst Monitor trigger 756678579 / 241223854 is not a GRB
  76. Fermi GRB 241223A: Global MASTER-Net observations report
  77. GRB 241223A: GOTO optical observations summary
  78. GRB 241105A: JWST photometric observations of the host galaxy
  79. GRB 241223A: Swift ToO observations
  80. EP241217a: e-MERLIN radio observations
  81. GRB 241223A: BALROG localization (Fermi Trigger 756648531 / GRB 241223506)
  82. GRB 241223A: Fermi GBM Final Real-time Localization
  83. The EP-WXT trigger 01709129287 is likely a flaring star
  84. Fermi trigger No 756447119: Global MASTER-Net observations report
  85. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  86. Fermi Gamma-ray Burst Monitor trigger 756447119/241221175 is not a GRB
  87. Fermi GRB 241221A: Global MASTER-Net observations report
  88. GRB 241221A: Fermi GBM Final Real-time Localization
  89. GRB 241217A/EP241217b: SOAR afterglow detection
  90. EP241217a: Liverpool Telescope optical upper limit
  91. EP241021a: VLA radio detection
  92. GRB 241218A: Mondy AZT-33IK optical upper limit
  93. EP241217a : Leavitt Observatory optical upper limit
  94. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  95. EP241217a: 1.6m Mephisto multi-band optical observations
  96. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  97. EP241217a: optical upper limit with the Liverpool Telescope
  98. GRB 241209B: EP-FXT afterglow detection
  99. Konus-Wind detection of GRB 241204A (short/hard)
  100. GRB 241218A: NOT optical upper limits

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