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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"

24475 results found.

  1. GRB 250103A: Montarrenti Observatory optical detection
  2. GRB 250103A: NOT optical observations
  3. GRB 250103A: Fermi GBM Observation
  4. GRB 250103B: LCOGT Optical Upper Limit
  5. IceCube-250102A: Upper limits from a search for additional neutrino events in IceCube
  6. Swift GRB 250103B: Global MASTER-Net observations report
  7. IceCube-250101A: Upper limits from a search for additional neutrino events in IceCube
  8. GRB 250103B: SVOM detection of a long burst
  9. Fermi GRB 250102A: Global MASTER-Net observations report
  10. GRB 250103A: SVOM/C-GFT optical upper limit
  11. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  12. IceCube Alert 250102.58: Global MASTER-Net observations report
  13. GRB 250103A: SVOM detection of a long burst (duplicate submission)
  14. GRB 250103A: SVOM detection of a long burst
  15. EP250101a: Xinglong optical upper limit
  16. GRB 250102A: Fermi GBM Final Real-time Localization
  17. LIGO/Virgo/KAGRA S241230bd: Upper limits from Swift/BAT-GUANO
  18. GRB 250101A: Swift-BAT refined analysis
  19. IceCube-250102A - IceCube observation of a high-energy neutrino candidate track-like event
  20. GRB 250101A NUTTelA-TAO / BSTI Early Measurements
  21. GRB 250101A: 1.6m Mephisto multi-band optical followup
  22. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  23. IceCube-250101A - IceCube observation of a high-energy neutrino candidate track-like event
  24. Fermi GRB 250101B: Global MASTER-Net observations report
  25. GRB 250101B: Fermi GBM Final Real-time Localization
  26. LIGO/Virgo/KAGRA S250101k: Updated Sky localization and Source Classification
  27. GRB 250101A: SVOM/C-GFT early optical observations
  28. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  29. GRB 250101A: MASTER earlier OT observations with SOSS emission features
  30. GRB 250101A: Swift detection of a burst with an optical counterpart
  31. Swift GRB250101.56: Global MASTER-Net observations report
  32. EP241217a: VLA Radio Detection

  33. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  34. LIGO/Virgo/KAGRA S250101k: Identification of a GW compact binary merger candidate
  35. LIGO/Virgo/KAGRA S241231bg: Updated NED Galaxies in the Localization Volume
  36. LIGO/Virgo/KAGRA S241231bg: Updated Sky localization and EM Bright Classification
  37. LIGO/Virgo/KAGRA S241230ev: Updated Sky localization
  38. LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume
  39. LIGO/Virgo/KAGRA S241230bd: Updated Sky localization
  40. GRB 241229A: EP-FXT X-ray afterglow confirmation
  41. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  42. LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
  43. LIGO/Virgo/KAGRA S241230ev: Identification of a GW compact binary merger candidate
  44. IceCube-Cascade 241228A: Upper limits from a search for additional neutrino events in IceCube
  45. GRB 241229B: SVOM/VT optical candidate
  46. GRB 241229A: Swift-XRT observations
  47. Konus-Wind detection of GRB 241228A
  48. EP240702a: 7DT Optical upper limits
  49. GRB 240606B: 7DT Optical upper limits
  50. Fermi trigger No 757231333: Global MASTER-Net observations report
  51. LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate
  52. GRB 241229B: Swift-BAT refined analysis
  53. LIGO/Virgo/KAGRA S241225v: Updated Sky localization
  54. LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification
  55. GRB 241229C: Fermi GBM Final Real-time Localization
  56. GRB 241228B: Fermi GBM Observation
  57. GRB 241229B: Fermi GBM Observation
  58. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  59. GRB 241229B: Swift-XRT refined Analysis
  60. IceCube-241224A: No transient candidates from the Zwicky Transient Facility
  61. Swift GRB 241229B: Global MASTER-Net observations report
  62. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  63. GRB 241228A: Swift-BAT refined analysis
  64. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  65. GRB 241229B: Fermi GBM Final Real-time Localization
  66. GRB 241229A: SVOM detection of a long burst
  67. Fermi GRB 241228B: Global MASTER-Net observations report
  68. GRB 241228A: Fermi GBM Observation
  69. GRB241228B: GROWTH-India Telescope optical observations
  70. Swift GRB 241228A: Global MASTER-Net observations report
  71. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  72. GRB 241228A: Swift-XRT refined Analysis
  73. GRB 241228B: GOTO possible optical counterpart candidate
  74. GRB 241228B: Fermi GBM Final Real-time Localization
  75. GRB 241228A: Swift detection of a burst
  76. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  77. LIGO/Virgo/KAGRA S241225c: Two counterpart neutrino candidates from IceCube neutrino searches
  78. GRB 241223A: GRBAlpha detection
  79. GRB 241212A: VZLUSAT-2 detection
  80. Fermi GRB 241226A: Global MASTER-Net observations report
  81. GRB 241226A: Fermi GBM Final Real-time Localization
  82. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  83. GRB 241223A: Fermi GBM Detection
  84. Fermi trigger No 756678579: Global MASTER-Net observations report
  85. LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate
  86. EP241223a
  87. IceCube-241224A - IceCube observation of a high-energy neutrino candidate track-like event
  88. IceCube Alert 241224.30: Global MASTER-Net observations report
  89. EP241223a: Global MASTER-Net observations report
  90. GRB241113A: 7DT Optical upper limits
  91. Fermi GRB 241223A: Global MASTER-Net observations report
  92. GRB 241223A: GOTO optical observations summary
  93. GRB 241105A: JWST photometric observations of the host galaxy
  94. EP241217a: e-MERLIN radio observations
  95. GRB 241223A: BALROG localization (Fermi Trigger 756648531 / GRB 241223506)
  96. GRB 241223A: Fermi GBM Final Real-time Localization
  97. Fermi trigger No 756447119: Global MASTER-Net observations report
  98. Fermi GRB 241221A: Global MASTER-Net observations report
  99. GRB 241221A: Fermi GBM Final Real-time Localization
  100. GRB 241218A: Mondy AZT-33IK optical upper limit

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