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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"

32715 results found.

  1. GRB 240606B: 7DT Optical upper limits
  2. LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate
  3. GRB 241229B: Swift-BAT refined analysis
  4. LIGO/Virgo/KAGRA S241225v: Updated Sky localization
  5. LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification
  6. GRB241229B: UVOT upper limits
  7. GRB 241228B: D50 optical detection
  8. GRB 241228B: Fermi GBM Observation
  9. GRB 241229B: Fermi GBM Observation
  10. GRB 241229A: Swift ToO observations
  11. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  12. GRB 241228A: Mondy optical afterglow observations
  13. IceCube-241224A: No transient candidates from the Zwicky Transient Facility
  14. Swift GRB 241229B: Global MASTER-Net observations report
  15. GRB 241229A: GOTO optical upper limits
  16. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  17. GRB 241228A: NOT optical upper limits
  18. GRB 241228B: LCO optical observation
  19. GRB 241228A: Swift-BAT refined analysis
  20. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  21. Fermi GRB 241228B: Global MASTER-Net observations report
  22. GRB 241228A: Fermi GBM Observation
  23. GRB241228B: GROWTH-India Telescope optical observations
  24. Swift GRB 241228A: Global MASTER-Net observations report
  25. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  26. GRB 241228B: GOTO24jmz optical follow-up observations
  27. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  28. GRB 241228A: GROWTH-India telescope optical upper limit
  29. GRB 241228B: Swift ToO observations
  30. GRB 241228B: TRT optical counterpart confirmation
  31. GRB 241228A: Swift/UVOT Upper Limits
  32. GRB 241228B: GOTO possible optical counterpart candidate
  33. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  34. GRB 241223A: GRBAlpha detection
  35. GRB 241212A: VZLUSAT-2 detection
  36. GRB 241217A/EP241217b: continued SOAR observations
  37. Fermi GRB 241226A: Global MASTER-Net observations report
  38. EP241223a: Mondy AZT-33IK optical observations
  39. GRB 241029A: LCO optical observation
  40. GRB 241223A: Swift-XRT observations
  41. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  42. GRB 241029A: AbAO AS-32 optical observations
  43. LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate
  44. EP241223a
  45. EP241223a: Global MASTER-Net observations report
  46. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  47. GRB241113A: 7DT Optical upper limits
  48. Fermi GRB 241223A: Global MASTER-Net observations report
  49. GRB 241223A: GOTO optical observations summary
  50. GRB 241105A: JWST photometric observations of the host galaxy
  51. GRB 241223A: Swift ToO observations
  52. EP241217a: e-MERLIN radio observations
  53. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  54. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  55. Fermi GRB 241221A: Global MASTER-Net observations report
  56. GRB 241217A/EP241217b: SOAR afterglow detection
  57. EP241217a: Liverpool Telescope optical upper limit
  58. EP241021a: VLA radio detection
  59. GRB 241218A: Mondy AZT-33IK optical upper limit
  60. EP241217a : Leavitt Observatory optical upper limit
  61. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  62. EP241217a: 1.6m Mephisto multi-band optical observations
  63. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  64. GRB 241218A: Swift/UVOT Upper Limits
  65. EP241217a: optical upper limit with the Liverpool Telescope
  66. GRB 241209B: EP-FXT afterglow detection
  67. Konus-Wind detection of GRB 241204A (short/hard)
  68. GRB 241218A: NOT optical upper limits
  69. GRB 241218A: Swift-BAT refined analysis
  70. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  71. EP 241217a: NIR detection with P200/WIRC
  72. EP 241217a: Possible J-band detection with WINTER
  73. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  74. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  75. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  76. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  77. GRB 241217A / EP241217b: NOT optical upper limits
  78. GRB 241218A: REM optical upper limit
  79. GRB 241217A/EP241217b: REM optical/NIR upper limits
  80. EP241217a: REM optical/NIR upper limits
  81. GRB 241218a: Liverpool Telescope optical follow-up
  82. GRB 241217a: Liverpool Telescope optical follow-up
  83. EP241217a: Liverpool Telescope optical follow-up
  84. EP241217a: NOT optical observations
  85. EP241217a: GROWTH-India Telescope optical observations
  86. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  87. EP241119a: 7DT Optical upper limits
  88. EP241217b: Global MASTER-Net observations report
  89. GRB 241209A: ATCA radio follow-up observations
  90. EP241217a: Xinglong optical follow-up observations
  91. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  92. GRB 241218A: LCOGT Optical Upper Limit
  93. EP241217a: Global MASTER-Net observations report
  94. GRB 241217A: GMG Optical Upper Limit
  95. GRB 241217A : SVOM/VT optical afterglow detection
  96. GRB 241217A: LCO optical upper limit
  97. GRB 241217A: GRANDMA/TAROT optical upperlimits
  98. EP241217a: Swift-XRT Detection
  99. EP241217A: Non-detection from Fermi-GBM Observations
  100. EP241217a: Gemini-North spectroscopic redshift z = 4.59

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