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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"

45418 results found.

  1. GRB 990510: BeppoSAX/GRBM observations
  2. GRB990510 optical observations
  3. GRB990510
  4. GRB 990510 optical observations
  5. GRB 990510 optical observations
  6. Galactic extinction towards GRB 990510
  7. GRB990510: NFI X-ray source
  8. GRB 990510 optical observations
  9. IPN localization of GRB990510
  10. GRB 990506 Radio Observations
  11. GRB 990123, optical monitoring
  12. GRB 990506: BATSE Observations
  13. GRB 990506, optical observations
  14. GRB 990510: Final BeppoSAX-WFC Coordinates
  15. GRB 990506, Optical Observations
  16. GRB 990506 optical observations
  17. GRB 990506 optical observations
  18. GRB 990506, optical observations
  19. GRB990506 observation plan
  20. Refined IPN error box for GRB990506
  21. GRB 990506: Limits on the possible optical transient
  22. GRB 990506, armchair astronomy
  23. GRB 990506, optical observations from +1 to +3 hours
  24. GRB 990506, optical observations
  25. GRB990506 Optical observations
  26. New IPN/RXTE error box for GRB990506
  27. IPN localization for GRB990506
  28. GRB 970228: Redshift and properties of the host galaxy
  29. IPN localization of GRB990427
  30. GRB981220 VLBA observations
  31. GRB980425 Optical observations of exponential decline at late time
  32. GRB990321 REFINED IPN ANNULUS
  33. GRB990323 PRECISE IPN POSITION
  34. GRB990321 IPN TRIANGULATION
  35. GRB 990316 Optical Observations
  36. GRB 990316, Radio observations
  37. GRB 990316, Optical observations
  38. GRB990316, Optical observations
  39. GRB 990316 optical observations
  40. GRB990316: simultaneous optical observation
  41. GRB990316 - Optical null results
  42. ASM/IPN error box for GRB 990308 (BATSE #7457)
  43. GRB990308 not a new SGR
  44. GRB 990308a and GRB 990308b
  45. GRB990308 (Trig. 7457), optical observations
  46. GRB990308, Possible new SGR~0209+70
  47. GRB981220, IPN localization
  48. GRB 981220, radio observations
  49. GRB 990123, Field Photometry
  50. GRB 990217 Optical Observations
  51. GRB 990217, radio observations
  52. BATSE Resumes Normal Operations
  53. GRB990217: BeppoSAX/GRBM data
  54. Optical Observations of GRB990217
  55. GRB990123: Caltech STIS Photometry and Images
  56. GRB990123 observations
  57. GRB990217, WFC position
  58. GRB990123, Optical Observation
  59. GRB 990123: Discovery of the Probable Host Galaxy
  60. GRB 990123: Reduced HST Images
  61. For Immediate Posting to GCN - HST Data GRB 990123 Available
  62. GRB19990123 observations
  63. GRB 990123: BVRI standards in the field
  64. GRB 990123: Updated Keck Spectroscopy Results
  65. GRB981220, field photometry
  66. GRB 990123 NOT Spectrum Update
  67. GRB990123, Optical observation
  68. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  69. GRB 990123: Publicly available reduced HST images
  70. GRB990123, Upcoming HST Service Observations
  71. GRB990123, 15-GHz limits
  72. GRB 990123: New Constraints on Possible Foreground Galaxies
  73. GRB990123 Optical Observations
  74. GRB990123, Probability of gravitational lensing
  75. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  76. GRB 990123: Continued Radio Observations
  77. GRB990123, Preliminary Lens Search Results
  78. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  79. On the Lensing Interpretation of GRB 990123
  80. Search for Potential Images of GRB 990123
  81. Search for Potential Images of GRB 990123
  82. GRB990123, Optical BVRI Observations
  83. GRB 990123: near-infrared observations.
  84. GRB990123, OSSE observations
  85. GRB990123: NIR Observation
  86. GRB990123, ASCA X-ray observation of afterglow
  87. "GRB 990123: New BV Observations"
  88. GRB 990123 Optical Follow-Up
  89. GRB 990123; Addendum to GCN 223
  90. GRB 990123: BATSE Observations
  91. GRB 990123 Keck Spectrum update
  92. GRB990123 IPN annulus
  93. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  94. GRB990123 Optical Observations
  95. GRB 990123 Spectroscopic Redshifts
  96. GRB 990123: New Optical Observations, Decay Measure
  97. GRB 990123 Optical Follow-Up
  98. GRB 990123: Possible Gravitationally Lensed Burst?
  99. GRB990123, optical observation
  100. GRB 990123 optical observations

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