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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"

16162 results found.

  1. GRB 231117A: Continued GTC Observations
  2. GRB 231117A: LDT Confirmation of Optical Fading
  3. GRB 231117A: Wendelstein Confirmation of Fading of the Optical Afterglow
  4. GRB 231117A : MITSuME Akeno optical afterglow candidate detection
  5. GRB 231118A: MeerLICHT afterglow detection
  6. GRB 231117A: OHP/T120 optical observations
  7. GRB 231118A: VLT/X-shooter redshift
  8. GRB 231117A: Pan-STARRS1 follow-up confirms rapid fading
  9. GRB 231117A: MAAO 0.7-m telescope optical upper limit
  10. GRB 231117A: AKO Follow-Up Observation
  11. GRB 231117A: 10 GHz VLA detection
  12. GRB 231118A: Las Cumbres optical detection
  13. GRB 231118A: LCOGT Optical Observations
  14. GRB 231118A: MASTER OT observation
  15. GRB 231118A: Continued Skynet Observations
  16. GRB 231118A: Skynet Optical Afterglow Discovery
  17. GRB 231117A: ePESSTO+ host galaxy redshift confirmation
  18. GRB 231117A: Keck spectroscopy of afterglow candidate
  19. GRB 231115A: Wendelstein Optical/Infrared Observations
  20. GRB 231115A: JinShan optical upper limits
  21. GRB 231117A: GIT optical follow-up
  22. GRB 231117A: LT observations consistent with fading
  23. GRB 231117A: Keck observations indicate presence of optical afterglow in z~0.3-0.5 galaxy
  24. GRB 231117A: REM optical and NIR early-time observations
  25. GRB 231117A: AKO Optical Upper Limit
  26. GRB 231117A: ATLAS non-detection of an optical counterpart
  27. GRB 231115A : OHP/T120 optical upper limit
  28. GRB 231115A: optical observations from INAF observatories
  29. GRB 231117A : MITSuME Akeno optical upper limits
  30. GRB 231117A: GOTO optical upper limits
  31. GRB231115A: Liverpool Telescope imaging
  32. GRB 231115A: NuSTAR Follow-Up Observations
  33. GRB 231115A: Swift-XRT and Swift-UVOT observations
  34. GRB 231115A : MITSuME Akeno and Okayama optical upper limits
  35. GRB 231115A: Gaoyazi/GOT follow-up and archival observations
  36. GRB 231115A: archival Chandra X-ray observations
  37. GRB 231115A: Kinder observations with Lulin observatory
  38. GRB 231115A: GOTO pre-burst limits of AT2023xvj
  39. GRB 231115A: pre-burst ZTF upper limits for GRB optical counterpart candidate
  40. GRB 231106A: TESS identification of candidate optical counterpart
  41. GRB 231115A: MASTER optical observations
  42. GRB 231115A: archival HST observations
  43. GRB 231115A: GROWTH-India discovery of a potential optical counterpart
  44. GRB 231111A: Xinglong-2.16m optical observations
  45. GRB 231111A: TNG tentative redshift
  46. GRB 231111A: Leavitt Observatory optical observations
  47. GRB231111A: Optical follow-up observations with Mephisto
  48. GRB 231111A: GMG observation upper limit
  49. GRB 231111A: Osservatorio Astronomico "Nastro Verde" optical observations with detection of an optical counterpart
  50. GRB 231110A: Terskol Zeiss-2000 optical upper limit
  51. GRB 231111A: Mondy optical observations
  52. GRB 231110A: GOTO optical upper limits
  53. GRB 231110A: SAO RAS optical observations
  54. GRB231111A: YAHPT Observations
  55. GRB231111A: GIT confirmation of the optical afterglow
  56. GRB 231111A: MASTER OT earlier detection
  57. GRB 231111A: Nanshan/HMT optical observations
  58. GRB 231111A: Swift detection of a burst with an optical counterpart
  59. IceCube-231103A: No candidates from the Zwicky Transient Facility
  60. GRB 231104A: FRAM-ORM optical limit
  61. GRB 231104A: Wendelstein Optical/Infrared Observations
  62. GRB 231104A: 3.6m DOT optical upper limit
  63. GRB 231104A: NOT upper limit
  64. GRB 231104A: Swift/UVOT Upper Limits
  65. GRB231104A: LCOGT Optical Upper Limits
  66. GRB 231024A: AKO Optical Counterpart Candidate
  67. GRB 231024A: Fermi GBM Observation
  68. GRB 231024A: X-shooter spectroscopy of AT2023vuc/GOTO23baj reveals a young supernova with flash ionisation features
  69. GRB 231024A: LCOGT and ZTF detections of the GOTO optical counterpart candidate
  70. GRB 231024A: GOTO optical counterpart candidate
  71. The photometry of the transient in Messier 31 field: GMG observation
  72. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  73. GRB 231017A: 1.3m DFOT Optical upper limit
  74. IceCube-231004A: Upper limits from Fermi-GBM Observations
  75. GRB 231017A: GOTO optical upper limits
  76. GRB 231017A: JinShan optical upper limit
  77. IC231004A: Classification of AT2023uqf/ZTF23abidzvf as a rapidly-evolving supernova with CSM interaction
  78. GRB 231017A: Las Cumbres optical upper limit
  79. GRB 231017A: LCOGT Optical Upper Limits
  80. GRB231017A: GROWTH-India upper limits on the optical afterglow
  81. (correction) Discovery of an optical transient with strong flaring activity: a new blazar candidate in the Messier 31 field
  82. Discovery of an optical transient with strong flaring activity: a new blazar candidate in the Messier 31 field.
  83. GRB 230827B: 10.4m GTC spectroscopic redshift
  84. Correction to Fermi GBM Statement for Trigger 716527670/230916144
  85. GRB 230812B : optical observations from MISTRAL at Observatoire de Haute-Provence
  86. GRB 230918B: GOTO detection of a fast-rising transient in the GBM localisation region
  87. AT 2023sva: NOT observations of the ZTF candidate afterglow
  88. ZTF and SEDM Observations of the Candidate Optical Afterglow AT 2023sva
  89. GRB 230906A: optical counterpart
  90. GRB 230911A: Swift-XRT afterglow detection
  91. GRB 230911A: GOTO optical counterpart candidate
  92. GRB230911C: BOOTES-6/DPRT optical upper limit
  93. GRB230911C: LCOGT Optical Upper Limits
  94. GRB 230911C: Swift/UVOT Upper Limits
  95. GRB 230911C: GOTO optical upper limits
  96. GRB 230903A: TESS observations of optical emission
  97. GRB 230906A: Swift/UVOT Upper Limits
  98. GRB 230205A: LBT spectroscopy of two host galaxy candidates
  99. GRB 230903A: VLT/X-shooter optical observations
  100. GRB 230903A: LCOGT Optical Upper Limits

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