Jean Tate

2015-Sep-24, 10:53 PM

I'm going through "Radio Properties of Infrared Selected Galaxies in the IRAS 2 Jy Sample", by Yun, Reddy, and Condon; link to the ADS abstract (http://adsabs.harvard.edu/abs/2001ApJ...554..803Y): http://adsabs.harvard.edu/abs/2001ApJ...554..803Y

I have some questions about this, and am hoping someone can help.

Look at Fig 6; the caption reads "Distribution of q values plotted as a function of IRAS 60 μm luminosity. The solid line marks the average value of q = 2.34 while the dotted lines delineate the “radio-excess” (below) and “infrared-excess” (above) objects, delineated for having 5 times larger radio and infrared flux density than the expected values from the linear radio-FIR relation, respectively."

The caption mentions "the linear radio-FIR relation", but I cannot find it anywhere in the paper (in quantitative form)! :eek:

The closest to such a thing that I can find is equation (4), "A formal fit to the observed radio-FIR luminosity correlation", which relates 1.4 GHz and 60 μm luminosities, as defined in equations (1) and (2).

You might think that "the linear radio-FIR relation" and "the observed radio-FIR luminosity correlation" are the same; however, that cannot be ... because, by definition, q includes "S100μm", which is the IRAS 100 μm band flux density in Jy.

So, quantitatively, what is "the linear radio-FIR relation"?

If you can't work out what "having 5 times larger radio and infrared flux density than the expected values from the linear radio-FIR relation, respectively" is, quantitatively, from what's in the text of the paper, you can work it out from the y-intercepts in Fig 6, right?

Now, look at Fig. 6; in particular the axes ... notice something, um, peculiar? No? OK, try this: reading from the y-axis, what is the value of q, for the two dotted blue lines, and the red line? See it now?

So, what are the values of the y-intercepts (of the two blue lines*) in Fig 6?

Last (rhetorical) question: this paper has been cited over 500 times, per ADS; what did all those papers use, quantitatively, for "the linear radio-FIR relation"?

* the intercept for the red line is 2.34 ... it says so in the caption

I have some questions about this, and am hoping someone can help.

Look at Fig 6; the caption reads "Distribution of q values plotted as a function of IRAS 60 μm luminosity. The solid line marks the average value of q = 2.34 while the dotted lines delineate the “radio-excess” (below) and “infrared-excess” (above) objects, delineated for having 5 times larger radio and infrared flux density than the expected values from the linear radio-FIR relation, respectively."

The caption mentions "the linear radio-FIR relation", but I cannot find it anywhere in the paper (in quantitative form)! :eek:

The closest to such a thing that I can find is equation (4), "A formal fit to the observed radio-FIR luminosity correlation", which relates 1.4 GHz and 60 μm luminosities, as defined in equations (1) and (2).

You might think that "the linear radio-FIR relation" and "the observed radio-FIR luminosity correlation" are the same; however, that cannot be ... because, by definition, q includes "S100μm", which is the IRAS 100 μm band flux density in Jy.

So, quantitatively, what is "the linear radio-FIR relation"?

If you can't work out what "having 5 times larger radio and infrared flux density than the expected values from the linear radio-FIR relation, respectively" is, quantitatively, from what's in the text of the paper, you can work it out from the y-intercepts in Fig 6, right?

Now, look at Fig. 6; in particular the axes ... notice something, um, peculiar? No? OK, try this: reading from the y-axis, what is the value of q, for the two dotted blue lines, and the red line? See it now?

So, what are the values of the y-intercepts (of the two blue lines*) in Fig 6?

Last (rhetorical) question: this paper has been cited over 500 times, per ADS; what did all those papers use, quantitatively, for "the linear radio-FIR relation"?

* the intercept for the red line is 2.34 ... it says so in the caption