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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

32504 results found.

  1. GRB 241228A: Mondy optical afterglow observations
  2. IceCube-241224A: No transient candidates from the Zwicky Transient Facility
  3. Swift GRB 241229B: Global MASTER-Net observations report
  4. GRB 241229A: GOTO optical upper limits
  5. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  6. GRB 241228A: NOT optical upper limits
  7. GRB 241228B: LCO optical observation
  8. GRB 241228A: Swift-BAT refined analysis
  9. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  10. Fermi GRB 241228B: Global MASTER-Net observations report
  11. GRB 241228A: Fermi GBM Observation
  12. GRB241228B: GROWTH-India Telescope optical observations
  13. Swift GRB 241228A: Global MASTER-Net observations report
  14. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  15. GRB 241228B: GOTO24jmz optical follow-up observations
  16. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  17. GRB 241228A: GROWTH-India telescope optical upper limit
  18. GRB 241228B: Swift ToO observations
  19. GRB 241228B: TRT optical counterpart confirmation
  20. GRB 241228A: Swift/UVOT Upper Limits
  21. GRB 241228B: GOTO possible optical counterpart candidate
  22. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  23. GRB 241223A: GRBAlpha detection
  24. GRB 241212A: VZLUSAT-2 detection
  25. GRB 241217A/EP241217b: continued SOAR observations
  26. Fermi GRB 241226A: Global MASTER-Net observations report
  27. EP241223a: Mondy AZT-33IK optical observations
  28. GRB 241029A: LCO optical observation
  29. GRB 241223A: Swift-XRT observations
  30. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  31. GRB 241029A: AbAO AS-32 optical observations
  32. LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate
  33. EP241223a
  34. EP241223a: Global MASTER-Net observations report
  35. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  36. GRB241113A: 7DT Optical upper limits
  37. Fermi GRB 241223A: Global MASTER-Net observations report
  38. GRB 241223A: GOTO optical observations summary
  39. GRB 241105A: JWST photometric observations of the host galaxy
  40. GRB 241223A: Swift ToO observations
  41. EP241217a: e-MERLIN radio observations
  42. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  43. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  44. Fermi GRB 241221A: Global MASTER-Net observations report
  45. GRB 241217A/EP241217b: SOAR afterglow detection
  46. EP241217a: Liverpool Telescope optical upper limit
  47. EP241021a: VLA radio detection
  48. GRB 241218A: Mondy AZT-33IK optical upper limit
  49. EP241217a : Leavitt Observatory optical upper limit
  50. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  51. EP241217a: 1.6m Mephisto multi-band optical observations
  52. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  53. GRB 241218A: Swift/UVOT Upper Limits
  54. EP241217a: optical upper limit with the Liverpool Telescope
  55. GRB 241209B: EP-FXT afterglow detection
  56. Konus-Wind detection of GRB 241204A (short/hard)
  57. GRB 241218A: NOT optical upper limits
  58. GRB 241218A: Swift-BAT refined analysis
  59. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  60. EP 241217a: NIR detection with P200/WIRC
  61. EP 241217a: Possible J-band detection with WINTER
  62. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  63. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  64. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  65. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  66. GRB 241217A / EP241217b: NOT optical upper limits
  67. GRB 241218A: REM optical upper limit
  68. GRB 241217A/EP241217b: REM optical/NIR upper limits
  69. EP241217a: REM optical/NIR upper limits
  70. GRB 241218a: Liverpool Telescope optical follow-up
  71. GRB 241217a: Liverpool Telescope optical follow-up
  72. EP241217a: Liverpool Telescope optical follow-up
  73. EP241217a: NOT optical observations
  74. EP241217a: GROWTH-India Telescope optical observations
  75. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  76. EP241119a: 7DT Optical upper limits
  77. EP241217b: Global MASTER-Net observations report
  78. GRB 241209A: ATCA radio follow-up observations
  79. EP241217a: Xinglong optical follow-up observations
  80. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  81. GRB 241218A: LCOGT Optical Upper Limit
  82. EP241217a: Global MASTER-Net observations report
  83. GRB 241217A: GMG Optical Upper Limit
  84. GRB 241217A : SVOM/VT optical afterglow detection
  85. GRB 241217A: LCO optical upper limit
  86. GRB 241217A: GRANDMA/TAROT optical upperlimits
  87. EP241217a: Swift-XRT Detection
  88. EP241217A: Non-detection from Fermi-GBM Observations
  89. EP241217a: Gemini-North spectroscopic redshift z = 4.59
  90. EP241217a: Kinder optical follow-up observations
  91. GRB 241214A: GRBAlpha detection
  92. GRB 241213A (EP241213a): GRBAlpha detection
  93. GRB 241209D: GRBAlpha detection
  94. EP241217A: LCO optical observations
  95. EP241217a: Gemini-North detection of the likely optical counterpart
  96. EP241107a: VLA Radio Observation
  97. GRB 241213A: Swift-BAT refined analysis
  98. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  99. Konus-Wind detection of GRB 241213A (EP 241213a)
  100. GRB 241215A: Mondy AZT-33IK optical observations

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