Class F Spectra $--$ Flat Spectra

The small-diameter or compact sources, usually associated with the nuclear galaxies, tend to have flat-spectra. Radio sources with flat spectra ($\alpha$ $\le$ ) are objects in which the contribution to the observed emission is made by the compact core of the source and are believed to be young sources.

We subdivide the flat spectra into two :

• Class F1 : flat spectra with no detected turn over, and
• Class F2 : flat spectra with turn over.

The list of the sources having in Class F1 is given in the table 5.5 and the figure 5.14 shows few examples of spectra fall in the Class F1. The list of the sources having in Class F2 is given in the table 5.6 and the figure 5.15 shows few examples of spectra fall in the Class F2.

Table 5.5: List of Sources with Class F1 Spectra.

Sr. No.	Source Name	Sr. No.	Source Name	Sr. No.	Source Name
1.	0136+478	12.	0725-009	23.	1653+397
2.	0237+288	13.	0739+016	24.	1728+044
3.	0303+472	14.	1221+282	25.	1800+784
4.	0334-401	15.	1246-075	26.	1925+211
5.	0336+323	16.	1257-319	27.	2015+371
6.	0416-188	17.	1432-180	28.	2022+616
7.	0453-281	18.	1545+478	29.	2023+544
8.	0538-440	19.	1557-000	30.	2050+041
9.	0541-056	20.	1613+342	31.	2115+295
10.	0607-085	21.	1626-298	32.	2148+069
11.	0608-223	22.	1635+381	-	-

Figure 5.14: Sources with Class F1 Spectra.

Table 5.6: List of Sources with Class F2 Spectra.

Sr. No.	Source Name	Mag. Field	Sr. No.	Source Name	Mag. Field
-	-	(micro-gauss)	-	-	(micro-gauss)
1.	0102+584	49464.98	11.	1146+399	2311935.07
2.	0204-170	22009.26	12.	1219+484	78.44
3.	0217+738	6500.84	13.	1254+116	63.54
4.	0409+122	63.54	14.	1323+797	2.07
5.	0423-013	320094.85	15.	2025+032	210.04
6.	0530+135	1859.90	16.	2031+123	78.44
7.	0700+171	5918553.77	17.	2139+143	1826714.13
8.	0741+312	81768.64	18.	2146-154	129.66
9.	0828-375	946968.60	19.	2246-121	4386.41
10.	1107-448	44395.16	20.	2330+110	0.57

Figure 5.15: Sources with Class F2 Spectra.