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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"

32485 results found.

  1. GRB 241228A: Swift/UVOT Upper Limits
  2. GRB 241228B: GOTO possible optical counterpart candidate
  3. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  4. GRB 241223A: GRBAlpha detection
  5. GRB 241212A: VZLUSAT-2 detection
  6. GRB 241217A/EP241217b: continued SOAR observations
  7. Fermi GRB 241226A: Global MASTER-Net observations report
  8. EP241223a: Mondy AZT-33IK optical observations
  9. GRB 241029A: LCO optical observation
  10. GRB 241223A: Swift-XRT observations
  11. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  12. GRB 241029A: AbAO AS-32 optical observations
  13. LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate
  14. EP241223a
  15. EP241223a: Global MASTER-Net observations report
  16. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  17. GRB241113A: 7DT Optical upper limits
  18. Fermi GRB 241223A: Global MASTER-Net observations report
  19. GRB 241223A: GOTO optical observations summary
  20. GRB 241105A: JWST photometric observations of the host galaxy
  21. GRB 241223A: Swift ToO observations
  22. EP241217a: e-MERLIN radio observations
  23. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  24. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  25. Fermi GRB 241221A: Global MASTER-Net observations report
  26. GRB 241217A/EP241217b: SOAR afterglow detection
  27. EP241217a: Liverpool Telescope optical upper limit
  28. EP241021a: VLA radio detection
  29. GRB 241218A: Mondy AZT-33IK optical upper limit
  30. EP241217a : Leavitt Observatory optical upper limit
  31. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  32. EP241217a: 1.6m Mephisto multi-band optical observations
  33. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  34. GRB 241218A: Swift/UVOT Upper Limits
  35. EP241217a: optical upper limit with the Liverpool Telescope
  36. GRB 241209B: EP-FXT afterglow detection
  37. Konus-Wind detection of GRB 241204A (short/hard)
  38. GRB 241218A: NOT optical upper limits
  39. GRB 241218A: Swift-BAT refined analysis
  40. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  41. EP 241217a: NIR detection with P200/WIRC
  42. EP 241217a: Possible J-band detection with WINTER
  43. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  44. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  45. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  46. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  47. GRB 241217A / EP241217b: NOT optical upper limits
  48. GRB 241218A: REM optical upper limit
  49. GRB 241217A/EP241217b: REM optical/NIR upper limits
  50. EP241217a: REM optical/NIR upper limits
  51. GRB 241218a: Liverpool Telescope optical follow-up
  52. GRB 241217a: Liverpool Telescope optical follow-up
  53. EP241217a: Liverpool Telescope optical follow-up
  54. EP241217a: NOT optical observations
  55. EP241217a: GROWTH-India Telescope optical observations
  56. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  57. EP241119a: 7DT Optical upper limits
  58. EP241217b: Global MASTER-Net observations report
  59. GRB 241209A: ATCA radio follow-up observations
  60. EP241217a: Xinglong optical follow-up observations
  61. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  62. GRB 241218A: LCOGT Optical Upper Limit
  63. EP241217a: Global MASTER-Net observations report
  64. GRB 241217A: GMG Optical Upper Limit
  65. GRB 241217A : SVOM/VT optical afterglow detection
  66. GRB 241217A: LCO optical upper limit
  67. GRB 241217A: GRANDMA/TAROT optical upperlimits
  68. EP241217a: Swift-XRT Detection
  69. EP241217A: Non-detection from Fermi-GBM Observations
  70. EP241217a: Gemini-North spectroscopic redshift z = 4.59
  71. EP241217a: Kinder optical follow-up observations
  72. GRB 241214A: GRBAlpha detection
  73. GRB 241213A (EP241213a): GRBAlpha detection
  74. GRB 241209D: GRBAlpha detection
  75. EP241217A: LCO optical observations
  76. EP241217a: Gemini-North detection of the likely optical counterpart
  77. EP241107a: VLA Radio Observation
  78. GRB 241213A: Swift-BAT refined analysis
  79. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  80. Konus-Wind detection of GRB 241213A (EP 241213a)
  81. GRB 241215A: Mondy AZT-33IK optical observations
  82. GRB 241215A: Nanshan/HMT optical upper limit
  83. GRB 241215A: Montarrenti Observatory optical upper limit
  84. GRB 241215A: GROWTH-India telescope optical upper limit
  85. GRB 241209D: CALET Gamma-Ray Burst Monitor detection
  86. GRB 241209B: SVOM/VT optical continuous fading
  87. GRB 241213A: SVOM/VT optical candidate
  88. GRB 241213B: Tiled Swift observations
  89. GRB 241213A: Swift/UVOT Upper Limits
  90. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  91. GRB 241212A: Fermi GBM detection
  92. EP241208a: NOT optical upper limits
  93. GRB 241212A: Swift ToO observations
  94. GRB 241213A: LCOGT Optical Upper Limits
  95. EP 241208A : Detection of a long soft transient by SVOM/ECLAIRs
  96. EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
  97. GRB 241213A: REM optical/NIR upper limits
  98. GRB241212A: OHP/T193 optical observations
  99. GRB 241213A: SAO RAS optical upper limit
  100. LIGO/Virgo/KAGRA S241210fu: Updated Sky localization

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