Is a golem immune to a Dread Necromancer's Charnel Touch?

Question

Imagine a situation: you're a Dread Necromancer with a ring of spiderclimb, and you're stuck in the room with the only exit being guarded by a [nonspecific] golem. You're out of spells, but you still have your ability Charnel Touch, which is basically 1d8 Negative Energy damage per turn, on touch attack. Since it's (Su) ability, it goes tight through Golem's SR (if any)... But does it damage him, or is that bloody thing immune?

Golems are immune to, and I quote:

poison, sleep effects, paralysis, stunning, disease, death effects, and necromancy effects.

which would usually mean that golems are immune to Negative Energy damage since it's a necromatic effect, right? Well... Maybe.

Necromancy spells manipulate the power of death, unlife, and the life force. Spells involving undead creatures make up a large part of this school.

That's the entire description of the Necromancy school, and the splatbooks aren't giving too much extra info. We all know that various Inflict spells and the like come from Necromancy school, but is there anything in the books AT ALL that directly and undoubtedly ties Charnel Touch to "Necromancy Effects"? Even a simple "Negative Energy damage is a necromancy effect" would do, except I can't find anything resembling that.

I'm looking for RAW answers. That is, no speculations, and quotes, please.

Answer 1

Yes, it's immune.

But only because Charnel Touch says so; not due to necromancy nor any of the other construct immunities.

Charnel Touch (Su): [...] At will, but no more than once per round, she can make a melee touch attack against a living foe that deals 1d8 points of damage, +1 per four class levels. This touch heals undead creatures, restoring 1 hit point per touch, +1 per four class levels.

A golem is neither living nor undead, so it's not a valid target for Charnel Touch.

(MM3 p.215)
Living: Any creature with a Constitution score is a living creature. Constructs and undead are not living creatures.

Answer 2

Nothing says it is a Necromancy effect, so it isn’t one. In fact, supernatural abilities don’t typically have spell schools; a supernatural effect like charnel touch could specify it counts as being from a particular school, but they usually don’t and schools usually only apply to spells.

Consider the definition of a spell school:

Cutting across the categories of arcane and divine spells are the eight schools of magic. These schools represent the different ways that spells take effect.

School (Subschool)

Beneath the spell name is a line giving the school of magic (and the subschool, if appropriate) that the spell belongs to.

Almost every spell belongs to one of eight schools of magic. A school of magic is a group of related spells that work in similar ways.

^{(emphasis mine)}

So unless a supernatural ability directly replicates a named spell, or explicitly states that it counts as being an effect from a particular school, it doesn’t have any school at all.

Answer 3

"Charnel Touch (Su): Negative energy flows through a dread necromancer's body, concentrating in her hands. At will, but no more than once per round, she can make a melee touch attack against a living foe that deals 1d8 points of damage, +1 per four class levels. This touch heals undead creatures, restoring 1 hit point per touch, +1 per four class levels. A dread necromancer can use the spectral hand spell to deliver this attack from a distance."

Note the "living:" that does NOT apply to objects, constructs and/or undead.

EDIT: Overlooked the post from topquark, sorry.