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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

24705 results found.

  1. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  2. EP241107a: AbAO optical upper limit
  3. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  4. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  5. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  6. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  7. EP241109a: confirmation of a stellar flare by BOOTES-7
  8. GRB 241108A: Swift-XRT observations
  9. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  10. EP241107a: KAIT optical observations
  11. GRB 241030A: TESS observations
  12. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  13. EP241107a: Kinder optical follow-up observations
  14. GRB 241025A: radio detection with the VLA
  15. EP241107a: AKO Optical Afterglow Follow-Up Observations
  16. EP241107a: GSP detects optical counterpart
  17. GRB 241105A: SVOM/GRM observation
  18. EP241107a: OHP/T193 photometric and spectroscopic observations
  19. GRB 241105a: PRIME near-infrared upper limits
  20. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  21. EP241107a: GIT optical observations
  22. EP241107a: SVOM/C-GFT optical observations
  23. EP241107a: AKO Optical Afterglow Detection
  24. GRB 241025A: LBT optical observations
  25. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  26. GRB 241105A: Swift/UVOT Detection
  27. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  28. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  29. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  30. GRB 241105A: Swift-XRT afterglow detection
  31. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  32. GRB 241104A: Swift-XRT observations
  33. GRB 240511A: LCO upper limits
  34. GRB 241104A: Fermi GBM Observation
  35. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  36. GRB 241104A: SVOM/VT optical candidate
  37. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  38. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  39. EP241104a: EP detection of GRB 241104A X-ray emission
  40. GRB 241010A: host galaxy redshift z = 0.977
  41. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  42. GRB 240821A: further radio observations with the VLA
  43. EP241103a: GIT optical upper limit
  44. EP241021a: OHP/T193 further optical observations
  45. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  46. LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
  47. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  48. EP241103a: Swift XRT detection and improved X-ray position
  49. EP241021a: continued SOAR observations
  50. EP241101a: Optical upper limits with Kinder observations
  51. EP241101a: OHP/T193 optical observations
  52. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  53. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  54. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  55. EP241103a: GSP optical upper limit
  56. EP241103A: LCO optical observations
  57. EP241103a: an X-ray transient detected by Einstein Probe
  58. LIGO/Virgo/KAGRA S241101ee: Updated Sky localization
  59. S241102cy: Identification of a GW compact binary merger candidate
  60. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  61. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  62. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  63. GRB241030A: OHP/T193 optical observations
  64. GRB 241101A: FRAM-ORM optical limit
  65. LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate
  66. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  67. EP241021a: Upper limit from Konus-Wind observations
  68. GRB 241101A: Swift-BAT refined analysis
  69. GRB 241030A: further SAO RAS optical observations
  70. GRB 241030A: Optical Observations via Virtual Telescope Project
  71. EP241021a: Liverpool Telescope optical follow-up observations
  72. GRB 241030B: Swift-XRT refined Analysis
  73. GRB 241026A: SAO RAS optical observations
  74. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  75. GRB 241101A: Swift detection of a burst
  76. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  77. EP241021a: OHP/T193 optical observations
  78. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  79. GRB 241030B: Montarrenti Observatory optical upper limit
  80. EP241026b: Liverpool Telescope optical follow-up
  81. GRB 241030A: SAO RAS optical observations
  82. GRB 241030A: Fermi GBM Observation
  83. EP241021a: AMI-LA radio detection
  84. GRB 241030B : GIT optical upper limits
  85. GRB 241030B: LCOGT Optical Upper Limits
  86. GRB 241030B: Swift-BAT refined analysis
  87. GRB 241030A: Swift-BAT refined analysis
  88. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  89. GRB 241030B: Swift/UVOT Detection
  90. GRB 241029A: LCO optical detection
  91. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  92. GRB 241030B : MITSuME Akeno optical upper limits
  93. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  94. GRB 241030B: SVOM/VT optical afterglow observations
  95. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  96. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  97. GRB241030B: Fermi GBM Observation
  98. GRB 241030B: BTA observations
  99. GRB 241029A: SVOM/VT optical afterglow observations
  100. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry

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