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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"

21953 results found.

  1. GRB 241229A: Swift-XRT observations
  2. EP240702a: 7DT Optical upper limits
  3. GRB 240606B: 7DT Optical upper limits
  4. Fermi trigger No 757231333: Global MASTER-Net observations report
  5. GRB241229B: UVOT upper limits
  6. GRB 241228B: D50 optical detection
  7. GRB 241228B: Fermi GBM Observation
  8. GRB 241228B: Swift-XRT afterglow detection
  9. GRB 241229A: Swift ToO observations
  10. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  11. GRB 241228A: Mondy optical afterglow observations
  12. IceCube-241224A: No transient candidates from the Zwicky Transient Facility
  13. Swift GRB 241229B: Global MASTER-Net observations report
  14. GRB 241229A: GOTO optical upper limits
  15. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  16. GRB 241228A: NOT optical upper limits
  17. GRB 241228B: LCO optical observation
  18. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  19. Fermi GRB 241228B: Global MASTER-Net observations report
  20. GRB241228B: GROWTH-India Telescope optical observations
  21. Swift GRB 241228A: Global MASTER-Net observations report
  22. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  23. GRB 241228B: GOTO24jmz optical follow-up observations
  24. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  25. GRB 241228B: Swift ToO observations
  26. GRB 241228B: TRT optical counterpart confirmation
  27. GRB 241228A: Swift/UVOT Upper Limits
  28. GRB 241228B: GOTO possible optical counterpart candidate
  29. GRB 241217A/EP241217b: continued SOAR observations
  30. Fermi GRB 241226A: Global MASTER-Net observations report
  31. EP241223a: Mondy AZT-33IK optical observations
  32. GRB 241029A: LCO optical observation
  33. GRB 241223A: Swift-XRT observations
  34. GRB 241029A: AbAO AS-32 optical observations
  35. Fermi trigger No 756678579: Global MASTER-Net observations report
  36. IceCube Alert 241224.30: Global MASTER-Net observations report
  37. EP241223a: Global MASTER-Net observations report
  38. EP241223a: EP-WXT detection of a fast X-ray transient
  39. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  40. GRB241113A: 7DT Optical upper limits
  41. Fermi GRB 241223A: Global MASTER-Net observations report
  42. GRB 241223A: GOTO optical observations summary
  43. GRB 241105A: JWST photometric observations of the host galaxy
  44. GRB 241223A: Swift ToO observations
  45. EP241217a: e-MERLIN radio observations
  46. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  47. Fermi trigger No 756447119: Global MASTER-Net observations report
  48. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  49. Fermi GRB 241221A: Global MASTER-Net observations report
  50. EP241021a: VLA radio detection
  51. GRB 241218A: Mondy AZT-33IK optical upper limit
  52. EP241217a : Leavitt Observatory optical upper limit
  53. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  54. EP241217a: 1.6m Mephisto multi-band optical observations
  55. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  56. GRB 241218A: Swift/UVOT Upper Limits
  57. GRB 241218A: NOT optical upper limits
  58. EP 241217a: NIR detection with P200/WIRC
  59. EP 241217a: Possible J-band detection with WINTER
  60. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  61. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  62. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  63. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  64. GRB 241217A / EP241217b: NOT optical upper limits
  65. GRB 241218A: REM optical upper limit
  66. GRB 241217A/EP241217b: REM optical/NIR upper limits
  67. EP241217a: REM optical/NIR upper limits
  68. EP241217a: Liverpool Telescope optical follow-up
  69. EP241217a: NOT optical observations
  70. EP241217a: GROWTH-India Telescope optical observations
  71. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  72. EP241119a: 7DT Optical upper limits
  73. EP241217b: Global MASTER-Net observations report
  74. GRB 241209A: ATCA radio follow-up observations
  75. EP241217a: Xinglong optical follow-up observations
  76. EP241217a: Global MASTER-Net observations report
  77. GRB 241217A : SVOM/VT optical afterglow detection
  78. GRB 241217A: Swift-XRT afterglow detection
  79. GRB 241217A: GRANDMA/TAROT optical upperlimits
  80. EP241217a: Swift-XRT Detection
  81. EP241217A: Non-detection from Fermi-GBM Observations
  82. EP241217a: Gemini-North spectroscopic redshift z = 4.59
  83. EP241217a: Kinder optical follow-up observations
  84. EP241217A: LCO optical observations
  85. EP241217a: Gemini-North detection of the likely optical counterpart
  86. EP241217a: EP detection of an X-ray transient
  87. EP241107a: VLA Radio Observation
  88. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  89. GRB 241215A: Mondy AZT-33IK optical observations
  90. GRB 241212A: Swift-XRT observations
  91. GRB 241215A: Nanshan/HMT optical upper limit
  92. GRB 241215A: Montarrenti Observatory optical upper limit
  93. Integral GRB241215.58: Global MASTER-Net observations report
  94. GRB 241213B: Swift-XRT observations
  95. GRB 241213A: SVOM/VT optical candidate
  96. GRB 241213B: Tiled Swift observations
  97. GRB 241213A: Swift/UVOT Upper Limits
  98. EP241208a: NOT optical upper limits
  99. GRB 241212A: Swift ToO observations
  100. EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart

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