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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"

32490 results found.

  1. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  2. GRB 241228A: GROWTH-India telescope optical upper limit
  3. GRB 241228B: Swift ToO observations
  4. GRB 241228B: TRT optical counterpart confirmation
  5. GRB 241228A: Swift/UVOT Upper Limits
  6. GRB 241228B: GOTO possible optical counterpart candidate
  7. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  8. GRB 241223A: GRBAlpha detection
  9. GRB 241212A: VZLUSAT-2 detection
  10. GRB 241217A/EP241217b: continued SOAR observations
  11. Fermi GRB 241226A: Global MASTER-Net observations report
  12. EP241223a: Mondy AZT-33IK optical observations
  13. GRB 241029A: LCO optical observation
  14. GRB 241223A: Swift-XRT observations
  15. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  16. GRB 241029A: AbAO AS-32 optical observations
  17. LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate
  18. EP241223a
  19. EP241223a: Global MASTER-Net observations report
  20. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  21. GRB241113A: 7DT Optical upper limits
  22. Fermi GRB 241223A: Global MASTER-Net observations report
  23. GRB 241223A: GOTO optical observations summary
  24. GRB 241105A: JWST photometric observations of the host galaxy
  25. GRB 241223A: Swift ToO observations
  26. EP241217a: e-MERLIN radio observations
  27. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  28. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  29. Fermi GRB 241221A: Global MASTER-Net observations report
  30. GRB 241217A/EP241217b: SOAR afterglow detection
  31. EP241217a: Liverpool Telescope optical upper limit
  32. EP241021a: VLA radio detection
  33. GRB 241218A: Mondy AZT-33IK optical upper limit
  34. EP241217a : Leavitt Observatory optical upper limit
  35. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  36. EP241217a: 1.6m Mephisto multi-band optical observations
  37. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  38. GRB 241218A: Swift/UVOT Upper Limits
  39. EP241217a: optical upper limit with the Liverpool Telescope
  40. GRB 241209B: EP-FXT afterglow detection
  41. Konus-Wind detection of GRB 241204A (short/hard)
  42. GRB 241218A: NOT optical upper limits
  43. GRB 241218A: Swift-BAT refined analysis
  44. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  45. EP 241217a: NIR detection with P200/WIRC
  46. EP 241217a: Possible J-band detection with WINTER
  47. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  48. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  49. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  50. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  51. GRB 241217A / EP241217b: NOT optical upper limits
  52. GRB 241218A: REM optical upper limit
  53. GRB 241217A/EP241217b: REM optical/NIR upper limits
  54. EP241217a: REM optical/NIR upper limits
  55. GRB 241218a: Liverpool Telescope optical follow-up
  56. GRB 241217a: Liverpool Telescope optical follow-up
  57. EP241217a: Liverpool Telescope optical follow-up
  58. EP241217a: NOT optical observations
  59. EP241217a: GROWTH-India Telescope optical observations
  60. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  61. EP241119a: 7DT Optical upper limits
  62. EP241217b: Global MASTER-Net observations report
  63. GRB 241209A: ATCA radio follow-up observations
  64. EP241217a: Xinglong optical follow-up observations
  65. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  66. GRB 241218A: LCOGT Optical Upper Limit
  67. EP241217a: Global MASTER-Net observations report
  68. GRB 241217A: GMG Optical Upper Limit
  69. GRB 241217A : SVOM/VT optical afterglow detection
  70. GRB 241217A: LCO optical upper limit
  71. GRB 241217A: GRANDMA/TAROT optical upperlimits
  72. EP241217a: Swift-XRT Detection
  73. EP241217A: Non-detection from Fermi-GBM Observations
  74. EP241217a: Gemini-North spectroscopic redshift z = 4.59
  75. EP241217a: Kinder optical follow-up observations
  76. GRB 241214A: GRBAlpha detection
  77. GRB 241213A (EP241213a): GRBAlpha detection
  78. GRB 241209D: GRBAlpha detection
  79. EP241217A: LCO optical observations
  80. EP241217a: Gemini-North detection of the likely optical counterpart
  81. EP241107a: VLA Radio Observation
  82. GRB 241213A: Swift-BAT refined analysis
  83. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  84. Konus-Wind detection of GRB 241213A (EP 241213a)
  85. GRB 241215A: Mondy AZT-33IK optical observations
  86. GRB 241215A: Nanshan/HMT optical upper limit
  87. GRB 241215A: Montarrenti Observatory optical upper limit
  88. GRB 241215A: GROWTH-India telescope optical upper limit
  89. GRB 241209D: CALET Gamma-Ray Burst Monitor detection
  90. GRB 241209B: SVOM/VT optical continuous fading
  91. GRB 241213A: SVOM/VT optical candidate
  92. GRB 241213B: Tiled Swift observations
  93. GRB 241213A: Swift/UVOT Upper Limits
  94. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  95. GRB 241212A: Fermi GBM detection
  96. EP241208a: NOT optical upper limits
  97. GRB 241212A: Swift ToO observations
  98. GRB 241213A: LCOGT Optical Upper Limits
  99. EP 241208A : Detection of a long soft transient by SVOM/ECLAIRs
  100. EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart

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