The main page for Splatalogue features the Basic search capabilities for the Splatalogue database. Use of the Basic search is limited to:

  • Common astronomically detected molecules and vibrational states, such as CO, H2O, methanol, hydrogen cyanide, and others.
  • Predefined “filtered” sets of molecules, such as those relevant to diffuse clouds, comets, planetary atmospheres, etc.
  • Search criteria including user defined frequency ranges, as well as ALMA bands 3-9 and the primary GBT bands, and lower state energy bounds.

In all cases, the only shown frequencies are those which are NRAO recommended. These are typically selected as the most recently updated linelist from either JPL, CDMS, or SLAIM. Observed astronomical intensities for transitions found in the Lovas/NIST database are also included along with the NRAO recommended frequencies.


Basic search functionality on Splatalogue, with results for CO and 13 CO shown.

The following tables summarize the features on the Basic page, which are shown in Figure 2.1:

Search Feature Description
Quick Picker (left) Selected common astronomical molecules.
Search bar (center) Search for single molecule in database by common name or chemical formula.
Astronomical Filters (right) Pre-defined sets of astronomical molecules based on environment characteristics.

Table 1. Basic searching criteria for molecular data.

Only one of the three searching criteria can be used at once – e.g. you cannot conduct a search on the Basic page with CO on the quick picker and H2S (hydrogen sulfide) selected from the Search bar. However, these kinds of combined searches can be performed in the advanced page.

The following criteria can be appended to the search:

Query Filter Description
Telescope Bands Limit frequency range to selected observing band.
Redshift Provides redshifted frequencies (in red text) in addition to rest frequencies.
Energy range Limit transitions to those with lower state energies within the given range (in units of cm-1and K).
Frequency ranges Limit transitions to those within inputted frequency or wavelength range. Multiple ranges can be added by using the + Frequency button.

Table 2. Basic filtering criteria for molecular data.

In the results listing (bottom of Figure 2.1), a basic set of data is shown, ordered by ascending frequency. The columns for the results set are:

Column Description
Species Descriptive formula of molecular species. Each is hyperlinked to show the metadata (see Advanced) for that species.
Chemical Name Common chemical name for species in previous column.
Ordered Frequency NRAO recommended rest frequency (black) and redshifted frequency (red, default redshift = 0).
Resolved QNs Rotational/rovibrational quantum numbers associated with the transition.
CDMS/JPL intensity Boltzmann-weighted logarithmic intensity of transition, given at 300 K – typical for CDMS and JPL linelists.
Lovas/AST Intensity Observed astronomical intensity for given transition, either from astronomical survey or Lovas/NIST database.
EL (cm-1/K) Lower state energy of transition in both wavenumbers and Kelvin.
Linelist Master linelist of which NRAO recommended frequency is derived, typically CDMS/JPL or SLAIM.

Table 3. Columns in results set for a given search in the Basic window.

Further information regarding transitions is included in the Splatalogue database, but is not accessible from the Basic functionality. Instead, if more advanced quantities are needed (such as transition dipole matrix elements, or Einstein A coefficients, etc), please see the advanced section of this user manual.

All search results can be exported in a variety of common formats, found at the bottom of the search results page. Search results can be exported in comma (CSV) or tab delimited ASCII files, as well as in a Virtual Astronomical Observatory (VAO)-compliant TSV file for use in CASA.


Search result export options.