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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"

46042 results found.

  1. GRB 250101A: BOOTES-4/MET optical afterglow detection
  2. GRB 250101A: AKO Optical Afterglow Detection
  3. GRB 250101A: SAO RAS optical observations
  4. GRB 250101A: Enhanced Swift-XRT position
  5. LIGO/Virgo/KAGRA S250101k: Updated Sky localization and Source Classification
  6. GRB 250101A: Xinglong-2.16m spectroscopic redshift
  7. GRB 250101A: SVOM/C-GFT early optical observations
  8. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  9. GRB 250101A: MASTER earlier OT observations with SOSS emission features
  10. GRB 250101A: Nanshan/HMT optical observations
  11. GRB 250101A : GIT optical detection
  12. GRB 250101A: GMG Optical Observation
  13. GRB 250101A: Swift detection of a burst with an optical counterpart
  14. Swift GRB250101.56: Global MASTER-Net observations report
  15. GRB 241217a/EP241217b: ATCA Radio Detection
  16. EP241217a: VLA Radio Detection

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

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