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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"

20824 results found.

  1. EP241107a: AKO Optical Afterglow Follow-Up Observations
  2. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  3. GRB 241105A: SVOM/GRM observation
  4. EP241107a: OHP/T193 photometric and spectroscopic observations
  5. GRB 241105a: PRIME near-infrared upper limits
  6. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  7. EP241107a: GIT optical observations
  8. EP241107a: SVOM/C-GFT optical observations
  9. EP241107a: AKO Optical Afterglow Detection
  10. GRB 241025A: LBT optical observations
  11. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  12. GRB 241105A: Swift/UVOT Detection
  13. EP241101a: CrAO ZTSH optical observations
  14. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  15. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  16. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  17. GRB 241105A: Swift-XRT afterglow detection
  18. GRB 241104A: Swift-XRT observations
  19. GRB 240511A: LCO upper limits
  20. GRB 241104A: Fermi GBM Observation
  21. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  22. GRB 241104A: NOT optical non-detection
  23. GRB 241104A: SVOM/VT optical candidate
  24. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  25. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  26. EP241104a: EP detection of GRB 241104A X-ray emission
  27. GRB 241010A: host galaxy redshift z = 0.977
  28. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  29. GRB 240821A: further radio observations with the VLA
  30. EP241101a: EP-FXT observations update
  31. EP241103a: GIT optical upper limit
  32. EP241021a: OHP/T193 further optical observations
  33. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  34. EP241103a: GOTO optical upper limit
  35. EP241103a: Swift XRT detection and improved X-ray position
  36. EP241021a: continued SOAR observations
  37. EP241101a: Optical upper limits with Kinder observations
  38. EP241101a: OHP/T193 optical observations
  39. EP241103a: Gemini optical limits
  40. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  41. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  42. EP241103A: LCO optical observations
  43. EP241103a: an X-ray transient detected by Einstein Probe
  44. GRB 241030A: Rapid release of TESS data.
  45. S241102cy: Identification of a GW compact binary merger candidate
  46. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  47. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  48. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  49. GRB241030A: OHP/T193 optical observations
  50. GRB 241101A: FRAM-ORM optical limit
  51. LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate
  52. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  53. GRB 241030A: further SAO RAS optical observations
  54. GRB 241030A: Optical Observations via Virtual Telescope Project
  55. EP241021a: Liverpool Telescope optical follow-up observations
  56. GRB 241026A: SAO RAS optical observations
  57. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  58. GRB 241101A: Swift detection of a burst
  59. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  60. EP241021a: OHP/T193 optical observations
  61. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  62. GRB 241030B: Montarrenti Observatory optical upper limit
  63. EP241026b: Liverpool Telescope optical follow-up
  64. GRB 241030A: SAO RAS optical observations
  65. EP241021a: AMI-LA radio detection
  66. GRB 241030B : GIT optical upper limits
  67. GRB 241030B: LCOGT Optical Upper Limits
  68. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  69. GRB 241030B: Swift/UVOT Detection
  70. GRB 241029A: LCO optical detection
  71. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  72. GRB 241030B : MITSuME Akeno optical upper limits
  73. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  74. GRB 241030B: SVOM/VT optical afterglow observations
  75. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  76. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  77. GRB 241030B: BTA observations
  78. GRB 241029A: SVOM/VT optical afterglow observations
  79. GRB 241030B: Enhanced Swift-XRT position
  80. GRB 241030B: optical observations from the INAF Asiago Observatory
  81. GRB241030B: GRANDMA/TAROT Upper Limit
  82. GRB 241030B: SAO RAS optical observations
  83. GRB 241030B: AKO Optical Afterglow Detection
  84. GRB 241030B: Nanshan/HMT optical afterglow detection
  85. GRB 241030B: Swift detection of a burst
  86. GRB 240912A: radio detection with the VLA
  87. GRB 241030A: AKO Optical Afterglow Detection
  88. GRB 241030A: Swift/UVOT Detection
  89. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  90. GRB 241030A: SVOM/C-GFT optical observations
  91. GRB 241026A: LBT optical observations
  92. EP241021a: Optical rebrightening observations with Mephisto
  93. GRB 241030A: Multiband optical detection with Mephisto
  94. GRB 241030A: SVOM/VT optical afterglow observations
  95. GRB 241030A : MITSuME Akeno optical afterglow detection
  96. GRB 241030A: Enhanced Swift-XRT position
  97. GRB 241029A: GROWTH-India Telescope optical follow up
  98. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  99. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  100. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart

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