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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"

24459 results found.

  1. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  2. GRB 250114B: Swift-XRT observations
  3. GRB 250114B: OHP/T193 optical upper limit
  4. GRB 250114A: Swift-XRT refined Analysis
  5. Integral GRB250114.55: Global MASTER-Net observations report
  6. LIGO/Virgo/KAGRA S250114ax: NED Galaxies in the Localization Volume
  7. GRB 250113A: INTEGRAL/SPI-ACS detection
  8. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  9. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  10. Swift GRB250114A: Global MASTER-Net OT detection
  11. GRB 250114A: TRT optical observations
  12. Swift GRB 250114A: Global MASTER-Net observations report
  13. GRB 250114A: Swift detection of a burst with an optical counterpart
  14. GRB 250113A: SVOM/GRM observation of a long burst
  15. GRB 250107A: VZLUSAT-2 detection
  16. EP250109b: optical upper limits with the Liverpool Telescope
  17. GRB 250109A / EP250109a: GRBAlpha detection
  18. GRB 250107D: GRBAlpha detection
  19. GRB 250106A: Swift-XRT afterglow detection
  20. Fermi trigger No 758442826: Global MASTER-Net observations report
  21. EP250111a: KAIT optical observations
  22. GRB 250109A / EP250109a: Mephisto optical upper limits
  23. EP250108a: Mephisto detection
  24. EP250111a: Global MASTER-Net observations report
  25. EP250111a: Swift/XRT detection and fading
  26. EP250108a / AT 2025kg (the "kangaroo”): VLT/X-shooter spectroscopic redshift z = 0.176 and LFBOT classification
  27. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  28. GRB 250101B: Fermi GBM Observation
  29. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  30. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  31. Konus-Wind detection of GRB 250107C
  32. LIGO/Virgo/KAGRA S250109bi: Updated Sky localization
  33. LIGO/Virgo/KAGRA S250109f: Updated Sky localization
  34. LIGO/Virgo/KAGRA S250108eo: Updated Sky localization
  35. EP-WXT trigger EP250108a：Xinglong optical follow-up observations
  36. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  37. EP250108a: EP-FXT follow-up observation
  38. GRB 250109A: Fermi GBM Observation
  39. EP-WXT trigger EP250109a：Xinglong optical follow-up observations
  40. Konus-Wind detection of GRB 250107D (short/hard)
  41. IPN triangulation of GRB 250107D (short/hard)
  42. IPN triangulation of GRB 250107C
  43. GRB 250108B: Gemini-North likely redshift z = 2.197
  44. GRB 250108B: Swift-BAT refined analysis
  45. GRB 250108B: 1.3m DFOT upper limit
  46. GRB 250108B: REM optical/NIR upper limits
  47. GRB 250109A /EP250109a: Fermi GBM Final Localization
  48. EP250109a: SVOM/VT optical candidate
  49. EP250109a: Global MASTER-Net observations report
  50. EP250108a: Global MASTER-Net observations report
  51. LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate
  52. GRB 250108A: NOT optical upper limit
  53. LIGO/Virgo/KAGRA S250109f: Identification of a GW compact binary merger candidate
  54. GRB 250108B: Swift-XRT refined Analysis
  55. Swift GRB 250108B: Global MASTER-Net observations report
  56. GRB 250108B: Gemini-North Candidate Optical Afterglow Detection
  57. GRB 250103A: 1.6m Mephisto optical observations
  58. GRB 250108A: Swift-XRT afterglow detection
  59. GRB 250108A:SVOM/VT optical candidate
  60. LIGO/Virgo/KAGRA S250108eo: Identification of a GW compact binary merger candidate
  61. GRB 250103A: Swift-XRT afterglow detection
  62. GRB 250108A: SVOM detection of a soft long burst
  63. GRB 250107A: Fermi GBM Observation
  64. GRB 241228B: Fermi-LAT detection
  65. Fermi GRB 250107B: Global MASTER-Net observations report
  66. GRB 250107A: Swift/BAT-GUANO arcminute localization of a burst
  67. GRB 250107B: Fermi GBM Final Real-time Localization
  68. GRB 250107A: Fermi GBM Final Real-time Localization
  69. EPWXT01709129925: Xinglong optical observations
  70. GRB 250106A: NOT optical observations
  71. LIGO/Virgo/KAGRA S250104v: Updated Sky localization
  72. GRB 250103B: REM optical/NIR upper limits
  73. GRB 250101A: REM optical/NIR counterpart detection
  74. GRB 250106A: SVOM/VT optical candidate
  75. GRB 250106A: SVOM detection of a long burst
  76. Fermi trigger No 757753930: Global MASTER-Net observations report
  77. GRB 241229A: SVOM/VT optical upperlimit
  78. GRB 250103B: VLT/X-shooter spectroscopic redshift z = 1.416
  79. GRB 250101A: 1.3m DFOT optical afterglow detection
  80. GRB 241229A: 1.3m DFOT upper limit
  81. GRB 241228B: 1.3m DFOT Optical observations
  82. GRB 241228A: 1.3m DFOT upper limit
  83. GRB 250103B：SVOM/VT optical counterpart
  84. LIGO/Virgo/KAGRA S250104v: Identification of a GW compact binary merger candidate
  85. GRB 250103A: Montarrenti Observatory optical detection
  86. GRB 250103A: NOT optical observations
  87. GRB 250103A: Fermi GBM Observation
  88. GRB 250103B: LCOGT Optical Upper Limit
  89. IceCube-250102A: Upper limits from a search for additional neutrino events in IceCube
  90. Swift GRB 250103B: Global MASTER-Net observations report
  91. IceCube-250101A: Upper limits from a search for additional neutrino events in IceCube
  92. GRB 250103B: SVOM detection of a long burst
  93. Fermi GRB 250102A: Global MASTER-Net observations report
  94. GRB 250103A: SVOM/C-GFT optical upper limit
  95. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  96. IceCube Alert 250102.58: Global MASTER-Net observations report
  97. GRB 250103A: SVOM detection of a long burst (duplicate submission)
  98. GRB 250103A: SVOM detection of a long burst
  99. EP250101a: Xinglong optical upper limit
  100. GRB 250102A: Fermi GBM Final Real-time Localization

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