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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"

45726 results found.

  1. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  2. GRB 250101A: MASTER earlier OT observations with SOSS emission features
  3. GRB 250101A: Nanshan/HMT optical observations
  4. GRB 250101A : GIT optical detection
  5. GRB 250101A: GMG Optical Observation
  6. GRB 250101A: Swift detection of a burst with an optical counterpart
  7. Swift GRB250101.56: Global MASTER-Net observations report
  8. GRB 241217a/EP241217b: ATCA Radio Detection
  9. EP241217a: VLA Radio Detection

  10. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  11. LIGO/Virgo/KAGRA S250101k: Identification of a GW compact binary merger candidate
  12. GRB 241229B: Continued CrAO ZTSh observations
  13. LIGO/Virgo/KAGRA S241231bg: Updated NED Galaxies in the Localization Volume
  14. LIGO/Virgo/KAGRA S241231bg: Updated Sky localization and EM Bright Classification
  15. LIGO/Virgo/KAGRA S241230ev: Updated Sky localization
  16. LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume
  17. LIGO/Virgo/KAGRA S241230bd: Updated Sky localization
  18. GRB 241229A: EP-FXT X-ray afterglow confirmation
  19. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  20. GRB 241229B: SVOM/GRM observation
  21. LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
  22. EP241217A: J band upper limit by SYSU 80cm telescope
  23. LIGO/Virgo/KAGRA S241230ev: Identification of a GW compact binary merger candidate
  24. GRB 241229B: SAO RAS optical upper limit
  25. GRB 241228B: SAO RAS optical observations
  26. GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
  27. GRB 241229A: SAO RAS optical observations
  28. IceCube-Cascade 241228A: Upper limits from a search for additional neutrino events in IceCube
  29. GRB 241229B: SVOM/VT optical candidate
  30. GRB 241229A: Swift-XRT observations
  31. Konus-Wind detection of GRB 241228A
  32. GRB 241229A: EP-FXT afterglow candidates
  33. EP240702a: 7DT Optical upper limits
  34. GRB 240606B: 7DT Optical upper limits
  35. Fermi trigger No 757231333: Global MASTER-Net observations report
  36. LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate
  37. GRB 241229B: Swift-BAT refined analysis
  38. LIGO/Virgo/KAGRA S241225v: Updated Sky localization
  39. LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification
  40. Fermi Gamma-ray Burst Monitor trigger 757207662/241229978 (GRB 241229C) is not a GRB
  41. GRB241229B: UVOT upper limits
  42. GRB 241229C: Fermi GBM Final Real-time Localization
  43. GRB 241228B: D50 optical detection
  44. GRB 241228B: Fermi GBM Observation
  45. GRB 241228B: Swift-XRT afterglow detection
  46. GRB 241229B: Fermi GBM Observation
  47. GRB 241229A: Swift ToO observations
  48. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  49. GRB 241228A: Mondy optical afterglow observations
  50. GRB 241229B: Swift-XRT refined Analysis
  51. IceCube-241224A: No transient candidates from the Zwicky Transient Facility
  52. Swift GRB 241229B: Global MASTER-Net observations report
  53. GRB 241229A: GOTO optical upper limits
  54. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  55. GRB 241228A: NOT optical upper limits
  56. GRB 241228B: LCO optical observation
  57. GRB 241228A: Swift-BAT refined analysis
  58. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  59. GRB 241229B: Swift detection of a burst
  60. GRB 241229B: Fermi GBM Final Real-time Localization
  61. GRB 241229A: SVOM detection of a long burst
  62. Fermi GRB 241228B: Global MASTER-Net observations report
  63. GRB 241228A: Fermi GBM Observation
  64. GRB241228B: GROWTH-India Telescope optical observations
  65. Swift GRB 241228A: Global MASTER-Net observations report
  66. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  67. GRB 241228B: GOTO24jmz optical follow-up observations
  68. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  69. GRB 241228A: GROWTH-India telescope optical upper limit
  70. GRB 241228B: Swift ToO observations
  71. GRB 241228B: TRT optical counterpart confirmation
  72. GRB 241228A: Swift-XRT refined Analysis
  73. GRB 241228A: Swift/UVOT Upper Limits
  74. GRB 241228B: GOTO possible optical counterpart candidate
  75. GRB 241228A: Enhanced Swift-XRT position
  76. GRB 241228B: Fermi GBM Final Real-time Localization
  77. GRB 241228A: Swift detection of a burst
  78. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  79. LIGO/Virgo/KAGRA S241225c: Two counterpart neutrino candidates from IceCube neutrino searches
  80. GRB 241223A: GRBAlpha detection
  81. GRB 241212A: VZLUSAT-2 detection
  82. GRB 241217A/EP241217b: continued SOAR observations
  83. Fermi GRB 241226A: Global MASTER-Net observations report
  84. GRB 241226A: Fermi GBM Final Real-time Localization
  85. EP241223a: Mondy AZT-33IK optical observations
  86. GRB 241029A: LCO optical observation
  87. GRB 241223A: Swift-XRT observations
  88. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  89. GRB 241029A: AbAO AS-32 optical observations
  90. GRB 241223A: Fermi GBM Detection
  91. Fermi trigger No 756678579: Global MASTER-Net observations report
  92. LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate
  93. EP241223a
  94. IceCube-241224A - IceCube observation of a high-energy neutrino candidate track-like event
  95. IceCube Alert 241224.30: Global MASTER-Net observations report
  96. GRB 241219A: SVOM/GRM observation
  97. EP241223a: Global MASTER-Net observations report
  98. EP241223a: EP-WXT detection of a fast X-ray transient
  99. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  100. GRB241113A: 7DT Optical upper limits

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