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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

16152 results found.

  1. GRB 230812B: GAD Observatory optical observations (upper limit)
  2. GRB 230812B: iTelescope optical upper limit
  3. GRB 230812B: continued SAO RAS optical observation
  4. GRB230815A: BOOTES-6/DPRT optical upper limit
  5. GRB 230812B: Tautenburg observations
  6. GRB 230812B: continued AbAO optical afterglow observations
  7. GRB 230812B: Optical observaions from Rozhen Observatory
  8. GRB 230812B: Further Bassano Bresciano Observatory optical observations
  9. GRB 230812B: further SAO RAS optical observations
  10. GRB 230812B: CrAO ZTSh optical observations
  11. GRB 230812B: Koshka Zeiss-1000 optical observations
  12. GRB 230812B: GIT optical follow-up
  13. GRB 230812B: Leavitt Observatory optical observations
  14. GRB 230812B : optical observations from Observatoire de Haute-Provence
  15. GRB 230812B: Bassano Bresciano Observatory optical observations
  16. GRB 230812B: Faulkes Telescope North optical afterglow follow-up
  17. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
  18. GRB 230812B: OASDG optical observations
  19. GRB 230812B: AbAO optical observations
  20. GRB 230812B: Montarrenti Observatory optical observations
  21. GRB 230812B: SAO RAS optical observations
  22. GRB 230812B: Detected Optical Afterglow Candidate
  23. GRB 230812B: GMG - GRANDMA observations
  24. GRB 230812: Swift/UVOT Detection
  25. GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
  26. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  27. Fermi GRB 230812B: MASTER optical counterpart
  28. GRB 230812B: KAIT Optical Afterglow Candidate
  29. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  30. ZTF23aaoohpy/AT2023lcr: JWST observations consistent with the presence of a supernova
  31. GRB 230805B : MITSuME Akeno optical upper limits
  32. GRB 230805B : OHP/T193 optical upper limit
  33. GRB 230805B: Swift/UVOT Upper Limits
  34. GRB 230805B: Bassano Bresciano observatory upper limit
  35. GRB 230805B: BOOTES-6/DPRT optical upper limit and 1.5m OSN detection
  36. GRB 230805B: NOT optical afterglow confirmation
  37. GRB 230805B: SAO RAS optical observations
  38. GRB 230802A: Swift/UVOT Upper Limits
  39. GRB 230802A: BOOTES-5/JGT optical upper limit
  40. GRB 230723B: MITSuME Ishigaki optical observation
  41. GRB 230728A: BOOTES-1 optical upper limit
  42. GRB 230728A: LCOGT Optical Upper Limit
  43. GRB 230728A: Swift/UVOT Upper Limits
  44. GRB 230728A: NOT optical observations and possible host galaxy
  45. GRB 230723B: Further CAHA observations and host galaxy detection
  46. GRB 230723B: MITSuME Akeno optical afterglow candidate detection
  47. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  48. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  49. GRB 230723B: Montarrenti Observatory upper limit
  50. GRB 230723B: Optical afterglow candidate from CAHA
  51. GRB 230723B: Bassano Bresciano Observatory upper limit
  52. GRB 230723B: Optical limit from CAHA
  53. GRB 230723B: Swift/UVOT Upper Limits
  54. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  55. GRB 230328B: LBT detection of the likely host galaxy
  56. LIGO/Virgo/KAGRA S230627c: observations of ZTF23aaptsuy/AT2023lx in AbAO observatory
  57. GRB 230628E: Swift/UVOT Detection
  58. AT2023lcr (ATLAS23msn/ZTF23aaoohpy): ALMA 100 GHz Detection
  59. GRB 230628E - VLT spectroscopic observations
  60. ZTF23aaoohpy/AT2023lcr: LBT observations
  61. GRB230628E: VLT optical identification of afterglow candidate
  62. GRB 230628E: LCOGT Optical Upper Limit
  63. ZTF23aaoohpy /AT2023lcr: TNG NIR detection
  64. LIGO/Virgo/KAGRA S230627c: ATLAS information on the ZTF candidates
  65. ZTF23aaoohpy/AT2023lcr: further SAO RAS observations
  66. ATLAS23msn/ZTF23aaoohpy/AT2023lcr: Zeiss-1000 of Koshka observatory optical observations
  67. MAXI GRB 230623A: MASTER optical observations
  68. ZTF23aaoohpy/AT2023lcr: SAO RAS observations
  69. AT2023lcr: VLA radio detection
  70. ZTF23aaoohpy/AT2023lcr: Montarrenti Observatory optical observations
  71. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Swift/UVOT detection
  72. ZTF23aaoohpy/AT2023lc: Mondy optical observations
  73. AT2023lcr: Neil Gehrels Swift Observatory X-ray detection
  74. ZTF23aaoohpy/AT2023lcr: Keck/LRIS spectroscopy and redshift
  75. ZTF23aaoohpy/AT2023lcr: Xinglong-2.16m optical observations
  76. ZTF23aaoohpy/AT2023lcr: Liverpool Telescope detection
  77. ZTF23aaoohpy/AT2023lcr: OHP/T193 and OHP/T120 optical follow-up observations
  78. ZTF23aaoohpy/AT2023lcr: GOTO early optical observations and constraint
  79. GRB 230618A: Swift/UVOT Upper Limits
  80. GRB 230618A: KAIT Optical Observations
  81. GRB230618A: LCOGT Optical Observations
  82. LIGO/Virgo/KAGRA S230615az: T80S Search and Candidate Counterpart Identification
  83. LIGO/Virgo/KAGRA S230615az: Non-Detections of GROWTH-India Candidates from GECKO Optical Observations
  84. LIGO/Virgo/KAGRA S230615az: GOTO candidate counterparts
  85. GRB 230606A: LCOGT Optical Observations
  86. ZTF23aamxeqf/AT2023jxk: 1.3m DFOT Optical upper limit
  87. ZTF and GIT Observations of the Candidate Optical Afterglow AT2023jxk
  88. GRB 230606A: Gaoyazi/GOT optical upper limit
  89. GRB 230606A: BOOTES-5/JGT optical upper limit
  90. GRB 230606A: Swift/UVOT Upper Limits
  91. LIGO/Virgo/KAGRA S230518h: ATCA follow-up of candidate counterparts
  92. LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
  93. LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
  94. LIGO/Virgo/KAGRA S230518h: Swope Search and Candidate Counterpart Identification
  95. Improved IPN triangulation of GRB 230512A
  96. GRB 230512A: Nanshan/NEXT non-detection of GRB afterglow candidate
  97. GRB 230512A: Liverpool Telescope observations
  98. GRB 230512A: GIT non detection of afterglow candidate
  99. GRB 230512A: Kitab possible afterglow candidate
  100. GRB 230510A: OHP/T193 and OHP/T120 optical observations

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