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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"

32508 results found.

  1. IPN triangulation of GRB 241107A (short/hard)
  2. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  3. GRB 241025C: VZLUSAT-2 detection
  4. GRB 241025A: VZLUSAT-2 detection
  5. GRB 241018A: cubesat Avion detection
  6. GRB 241030B: TESS detection of optical counterpart
  7. LIGO/Virgo/KAGRA S241110br: Updated Sky localization
  8. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  9. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  10. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  11. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  12. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  13. EP241107a: AbAO optical upper limit
  14. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  15. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  16. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  17. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  18. EP241109a: confirmation of a stellar flare by BOOTES-7
  19. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  20. EP241107A: MASTER optical observations of xray transient
  21. EP241107a: KAIT optical observations
  22. GRB 241108A: Swift ToO observations
  23. GRB 241030A: TESS observations
  24. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  25. EP241107a: Kinder optical follow-up observations
  26. GRB 241025A: radio detection with the VLA
  27. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  28. EP241107a: AKO Optical Afterglow Follow-Up Observations
  29. EP241107a: GSP detects optical counterpart
  30. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  31. GRB 241105A: EP-FXT follow-up observations
  32. GRB 241105A: SVOM/GRM observation
  33. EP241107a: OHP/T193 photometric and spectroscopic observations
  34. GRB 241105a: PRIME near-infrared upper limits
  35. EP241107a: FTW Optical and NIR observations of the optical counterpart
  36. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  37. EP241107a: GIT optical observations
  38. EP241107a: Global MASTER-Net observations report
  39. EP241107a: SVOM/C-GFT optical observations
  40. EP241107a: AKO Optical Afterglow Detection
  41. GRB 241025A: LBT optical observations
  42. GRB241105A: Gemini-South Optical Afterglow Detection
  43. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  44. GRB 241105A: Swift/UVOT Detection
  45. EP241101a: CrAO ZTSH optical observations
  46. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  47. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  48. GRB 241030A: Mondy optical observations
  49. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  50. Konus-Wind detection of GRB 241105A (short with extended emission)
  51. Konus-Wind detection of GRB 241021A
  52. GRB 241105A: SVOM/VT optical afterglow observations
  53. GRB 241105A: Swift-XRT afterglow detection
  54. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  55. GRB 241104A: Swift-XRT observations
  56. GRB 240511A: LCO upper limits
  57. GRB 241104A: Fermi GBM Observation
  58. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  59. GRB 241105A: Swift ToO observations
  60. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  61. GRB 241104A: Swift ToO observations
  62. GRB 241104A: NOT optical non-detection
  63. GRB 241105A: GOTO tentative optical counterpart candidate
  64. Fermi GRB 241105A: Global MASTER-Net observations report
  65. GRB 241104A: SVOM/VT optical candidate
  66. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  67. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  68. GRB 241104A: SVOM/GRM observation
  69. EP241104a: EP detection of GRB 241104A X-ray emission
  70. GRB 241010A: host galaxy redshift z = 0.977
  71. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  72. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  73. GRB 240821A: further radio observations with the VLA
  74. Fermi GRB 241104A: Global MASTER-Net observations report
  75. GRB 241030A: GRBAlpha detection
  76. EP241101a: EP-FXT observations update
  77. EP241103a: GIT optical upper limit
  78. EP241021a: OHP/T193 further optical observations
  79. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  80. LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
  81. EP241103a: GOTO optical upper limit
  82. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  83. EP241101a: Possible detection of an optical counterpart with FTW
  84. EP241103a: Swift XRT detection and improved X-ray position
  85. EP241021a: continued SOAR observations
  86. EP241101a: Optical upper limits with Kinder observations
  87. EP241101a: OHP/T193 optical observations
  88. EP241103a: Gemini optical limits
  89. EP241103a: EP observation update
  90. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  91. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  92. EP241103a: GSP optical upper limit
  93. EP241103A: LCO optical observations
  94. EP241103a: Global MASTER-Net observations report
  95. GRB 241030A: Rapid release of TESS data.
  96. EP241101a: Global MASTER-Net observations report
  97. GRB 241029A: GRBAlpha detection
  98. LIGO/Virgo/KAGRA S241101ee: Updated Sky localization
  99. S241102cy: Identification of a GW compact binary merger candidate
  100. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate

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